Double stars I discovered!
comet....@yahoo.co.uk
pairs of stars in the northern skies in last couple of years, that
have not previously been recorded in the Washington Double Star
catalogues. I happen to come upon a few pairs that I believe should be
added to the catalog as potential true binaries. That is to say, I
believe the pairs are close enough in angular separation and display
siimilar stellar attributes to rank as genuine binaries, and not
merely line of sight optical doubles.
I checked my observation with the current WDS catalogue, listed here:
http://ad.usno.navy.mil/wds/wdstext.html
and they definitely aint listed there!! So these are genuine new
discoveries!!
I'm not sure where to send my observations, but I guess I should post
them to the astronomy groups here first to see if you guys have
already beaten me to these binaries!? :)
I like to announce to the astronomy groups that I have identified 3
pairs in total that I plan on investigating further in coming years.
They are:
FIRST PAIR (In Vulpecula):
RA 19h 52m 13.1s, Dec +27deg 27min 0.8arcsecs (Mag around 8.5)
RA 19h 52m 12.9s, Dec +27deg 26min 29.0arcsec (Mag
around 8.7)
The separation is approx 30" (30 arc-seconds as of May 17, 2009),
position is J2000.0 when I matched them to Stellarium software on my
PC
The next two pairs flank the star HP63952 in Ursa Major, to the north
of the Handle of the Plough.
PAIR TO THE RIGHT OF HP63952:
RA 13h 06m 23.8s, Dec +62deg 03min 44.6arcsec (Mag around
9.2)
RA 13h 06m 22.3s, Dec +62deg 03min 43.2arcsec (mag of
about 9.9)
Separation is about 22" (22 arc-seconds)
PAIR TO THE LEFT OF HP63952:
RA 13h 06m 23.2s, Dec +62deg 01min 08.6arcsec (magnitude
about 8.9)
RA 13h 06m 24.7s, Dec +62deg 00min 53.4arcsec (mag about
9.8)
Separation of approx 25" (25 arc-seconds)
They are fairly wide, but the stars are reddish in colour, so my guess
is they are red dwarfs and may be not too far away in distance, making
them appear wider in separation...
ukastronomy
are unlikely to be true binaries.
Martin Nicholson
Daventry, UK
comet....@yahoo.co.uk
wrote:
I wanted your advice why my discoveries not binaries please from
uk.sci.astronomy. Even if they're not true binaries, they still count
as legitimate double stars, don't they?
http://groups.google.com/group/sci.astro.amateur/browse_frm/thread/468c589eafa57a4a#
thank you
comet....@yahoo.co.uk
>
> thank you
I also like to further report that the star HP25753 (spectral type F0)
of mag 8.9 in constellation Cameolopardalis has a 10th magnitude
reddish companion at a separation of ~60 arcseconds. I have long
pondered about this one (given the rather large separation), but I
nonetheless suspect is a binary companion to this star which shares a
common proper motion with HP25753.
comet....@yahoo.co.uk
>
> - Show quoted text -
The final pair, that I'm still unsure about is in Lacerta at
(J2000.0):
RA 22 28 13.7, Dec +51 54 19.8 (mag ~9)
RA 22 28 15.8, Dec +51 54 39.5 (mag ~10)
Separation is about ~30 to 40 arcseconds (as of December 2008).
That's me done!
Mike Dworetsky
news:ab2c3c4e-1796-4203...@b1g2000vbc.googlegroups.com...
Robert Grant Aitken, the famous observer of double stars, set a general
criterion of likely physical pairing vs magnitude as log(rho) = 2.6 - 0.2 m
where rho is the separation in arcsec. If a pair fall within that limit,
then it is probably a true physical pair (more data would be needed to
clinch the identification) while if it is outside the limit, the pair is
probably optical (though with more data you might be able to prove the
opposite, such as spectral class, including luminosity classification,
proper motion and accurate radial velocity for example).
An example:
For mag 9.0, 2.6 -1.8 = 0.8 and 10^0.8 = 6.3 arcsec, so with your pairs
falling far outside that range they are very unlikely to be physical pairs
and are probably chance associations.
You will find Aitken's criterion discussed in
http://adsabs.harvard.edu/abs/1932MNRAS..92..596A
Aitken, R. G., MNRAS, 92, 596, 1932.
"What we know about double stars" (George Darwin Lecture)
From Simbad:
http://simbad.u-strasbg.fr/simbad/
Your first pair with separation around 31-32 arcsec is
BD+27 3542 (pm -1.40, -6.50 mas/yr) V = 8.69 (B-V = 0.76) and
HD 339063 (pm -0.50, -17.40 mas/yr) V = 8.69 (B-V = 0.53)
Errors quoted for components of pm are around 1-2 mas/yr, so this rules out
these stars being a common proper motion pair. Having the same magnitude
but different colours also is not what would be expected of a physical pair
at the same distance from us.
These are pretty small proper motions which also suggests these stars are
not nearby red dwarves.
I don't have time to do all your pairs, and have to leave it to you.
--
Mike Dworetsky
(Remove pants sp*mbl*ck to reply)
ukastronomy
>
> I also like to further report that the star HP25753 (spectral type F0)
> of mag 8.9 in constellation Cameolopardalis has a 10th magnitude
> reddish companion at a separation of ~60 arcseconds. I have long
> pondered about this one (given the rather large separation), but I
> nonetheless suspect is a binary companion to this star which shares a
>
Where did you get the proper motion information from? It looks to me
as if Tycho 4085-2923-1 has a very different proper motion to Tycho
4085-2388-1. Or at least they do in the Tycho 2 Catalogue and in the
UCAC2 bright star Catalogue (both available via Vizier). What source
have you used that suggests they are a common proper motion pair?
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
> <comet.see...@yahoo.co.uk> wrote in message
>
> - Show quoted text -
Like I said before, the pairs are close enough in separation to rank
as true double stars and any physical association is only suspected.
I'd just leave it at that for now. They are still pairs I discovered!
No???
eridanus riviera
>
> - Show quoted text -
Sure. Just dont let it surprise you when your doubles become
nonexistent with PM in like a couple of centuries from now.
ps: are you abdul ahad in another disguise? DOH!
ukastronomy
>
> - Show quoted text -
Mike has given a good summary of the science and all that I would add
is that although you have discovered nothing of significance you have
had fun and have learnt something new.
Pierre Vandevenne
> Like I said before, the pairs are close enough in separation to rank
> as true double stars and any physical association is only suspected.
> I'd just leave it at that for now. They are still pairs I discovered!
> No???
Sure. Sure. They are all yours. Enjoy!
comet....@yahoo.co.uk
>
> - Show quoted text -
As if WDS never recorded double's with separations more then 100 arc-
seconds wide!? Of course they do! And not all of them is confirmed to
be physical. :)
One pair I seen last summer is in Hercules, is starting to come to
view now in late May. Heres that pair with separation (your rho?) of
24.5 arc-seconds:
RA 18 24 59.6, Dec +16 41 55.5 (8th mag)
RA 18 24 58.0, Dec +16 42 00.6 (10th mag)
these are both red, so there is the spectral match. My sixth double
star discovery!!!
Mike Dworetsky
news:93128dd4-50ec-421e...@21g2000vbk.googlegroups.com...
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I have nothing at all against amateur astronomers enjoying looking at the
night sky. That's why it's there, isn't it? Just don't read more into the
observations than is warranted.
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
> "ukastronomy" <martin_piers_nichol...@yahoo.co.uk> wrote in message
>
> I have nothing at all against amateur astronomers enjoying looking at the
> night sky. That's why it's there, isn't it? Just don't read more into the
> observations than is warranted.
>
> --
> Mike Dworetsky
>
>
> - Show quoted text -
I totally agree. This business of 'hey i discovered this, and he
discovered that' is just pure fun. The night sky and its vast riches
in reality belong to no man...and the doubles do not even belong to
Struve or Herschel or Aitken. Any more than the Galilean moons belong
to Galileo :) LOL
Mike Dworetsky
news:af5b76f7-000a-4a4d...@h23g2000vbc.googlegroups.com...
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Except, of course, that we still attach the names of the discoverers to the
Struve, Herschel, and Aitken double stars in the various lists, e.g.,
Struve's discoveries are indicated with a capital sigma and a number.
comet....@yahoo.co.uk
Of course!
Out of interest, how complete is SIMBAD database /query system? I dont
think it includes every star in every catalog. I ask because theres
one pair in draco (the dragon) where my notes were in pencil and not
100% readable, very obscure, going back a long time, but I have them
as:
RA 12 18 43.9, Dec +65 53 59.5 (of ~9.5th magnitude)
RA 12 18 43.0, Dec +65 53 53.3 (of mag ~10)
This isn't in the WDS catalogue and the separation is about 14" (14
arc-seconds), just outside the Aitken critera for binary stars.
Funny thing is theres no mention of either of these stars in
SIMBAD...when I tried the coordinate query?
comet....@yahoo.co.uk
>
> - Show quoted text -
I have complete my analysis of the pair I reported in Lacerta. It is a
true "common proper motion" star and both components are of spectral
class A0 (white as Vega). They are also clearly identified in SIMBAD -
but as two separate stars:
Primary: HD 213128 -- Star
ICRS coord. (ep=2000) : 22 28 13.7025 +51 54 19.833
Proper motions mas/yr [error ellipse]: -2.60 0.50
Error ellipse: [1.70 1.60 90]
Spectral type: A0 D
V 8.88
Secondary: BD+51 3386 -- Star
ICRS coord. (ep=2000) : 22 28 15.8443 +51 54 39.408
Proper motions mas/yr [error ellipse]: -3.90 1.30
Error ellipse: [1.80 1.70 90]
Spectral type: A0 D ~
V 9.88
Their error ellipse overlap in propper moton, so I think this is a
binary! It should be in WDS catalog!
I have to fix my telescope collimations this weekend then, take
another peek at this binary :)
Mike Dworetsky
news:fe5a382a-7d1b-4936...@e24g2000vbe.googlegroups.com...
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MD says:
What sort of numbers do these data suggest?
Assuming that they are both roughly A0V (why the 1 mag difference in
brightness, then?) with absolute Mv = 1.0, then for say mag 9.0, the m-M is
8 mag or
m-M = 5logd -5; log d = 13/5 = 2.6; d ~ 400pc. Angular separation about 30
arcsec, so separation in plane of the sky is 30 x 400 AU = 12,000 AU. But
that's a minimum, because the stars may well not both be in the plane of the
sky. With masses of around 2.5 Msun each, Kepler's third law gives a
minimum period of sqrt([12000^3] / 5) = 588,000 yr. In reality they are
probably not at the same distance; suppose they are only different in
distance by 1pc? In that case they are not physically paired.
Given their tangential velocity difference is of the order of 4.74 x pm x d
= 4.74 x 0.001 x 400 ~ 2 km/sec may indicate something (and it could be
anything from about 4 to 0) but it could be fortuitous. Perhaps they are
members of a dispersing old cluster (similar to the Ursa Major group?).
If so, try widening the Simbad search to 10-20-30 arcmin and see if any
other similar stars (same m-M, same proper motion) come up.
Two stars do not make a loose cluster, but 5-10 might point at one. Let us
know.
Mike Dworetsky
news:c24b2568-4bfe-4746...@n21g2000vba.googlegroups.com...
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MD says:
I'm not sure--there may be somewhere an explanation of how stars get into
Simbad, and I don't think being only in the Guide Star Catalogue is enough,
so this may be the only source where there are any details at all.
comet....@yahoo.co.uk
>
> - Show quoted text -
The Hercules pair i now report with full confidense. I just saw them
at 0300 BST! The primary is in SIMBAD listed as BD+16 3495 -- Star
J2000 18 24 59.6, +16 41 55.5. It appears intensely red at 100x on my
Skywatcher!!! The secondry is much fainter than I imagine last year.
It looks bout magnitude 10.5 to 11-ish and I could not see its colour
and only detected with averted vision and squint. from north, it is
somewhere near 2:00 o'clock position if on clock face.
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
> <comet.see...@yahoo.co.uk> wrote in message
>
> MD says:
>
> What sort of numbers do these data suggest?
>
> Assuming that they are both roughly A0V (why the 1 mag difference in
> brightness, then?) with absolute Mv = 1.0, then for say mag 9.0, the m-M is
> 8 mag or
>
> m-M = 5logd -5; log d = 13/5 = 2.6; d ~ 400pc. Angular separation about 30
> arcsec, so separation in plane of the sky is 30 x 400 AU = 12,000 AU. But
> that's a minimum, because the stars may well not both be in the plane of the
> sky. With masses of around 2.5 Msun each, Kepler's third law gives a
> minimum period of sqrt([12000^3] / 5) = 588,000 yr. In reality they are
> probably not at the same distance; suppose they are only different in
> distance by 1pc? In that case they are not physically paired.
>
> Given their tangential velocity difference is of the order of 4.74 x pm x d
> = 4.74 x 0.001 x 400 ~ 2 km/sec may indicate something (and it could be
> anything from about 4 to 0) but it could be fortuitous. Perhaps they are
> members of a dispersing old cluster (similar to the Ursa Major group?).
>
> If so, try widening the Simbad search to 10-20-30 arcmin and see if any
> other similar stars (same m-M, same proper motion) come up.
>
> Two stars do not make a loose cluster, but 5-10 might point at one. Let us
> know.
>
> --
> Mike Dworetsky
>
>
> - Show quoted text -
MD, thank you for this inspiration. I will check this out!
comet....@yahoo.co.uk
>
> MD says:
>
> I'm not sure--there may be somewhere an explanation of how stars get into
> Simbad, and I don't think being only in the Guide Star Catalogue is enough,
> so this may be the only source where there are any details at all.
>
> --
> Mike Dworetsky
>
>
> - Show quoted text -
This is a major problem when things in the sky are not in SIMBAD. How
to prove these stars really exist?
I published my discoveries here:
http://uk.geocities.com/aa_spaceagent/Double-Stars.html
But I am still not happy with the pairs at:
Primary is in SIMBAD: BD+48 2520 -- Star
ICRS coord. (ep=2000) : 17 27 56.523 +47 54 30.72
Proper motions mas/yr [error ellipse]: -90.5 37.0 [5.1 5.0 90]
Spectral type: G0 D
V 9.1
The secondary is of V 9.75 but is not listed in SIMBAD.
The Separation A-B is just 10.5 arc-seconds making this a reasonably
close pair to be a genuine binary more than likely!
And the third pair Hercules I am going to have to take another look,
as I didn't really bother with it after one glimpse:
There is no inclusion of this pair in Washington Double Star catalogue
and there is no result in SIMBAD either. The only match I could find
was in Stellarium:
J2000.0: RA = 18 04 40.3, Dec = +23 57 52.3
Mags of ~9.5 and ~10.0, separation ~5 arcseconds apart! Both appeared
slightly reddish. True binary!
The location is actually very close to the star HP 88528
ukastronomy
>
> But I am still not happy with the pairs at:
>
> Primary is in SIMBAD: BD+48 2520 -- Star
> ICRS coord. (ep=2000) : 17 27 56.523 +47 54 30.72
> Proper motions mas/yr [error ellipse]: -90.5 37.0 [5.1 5.0 90]
> Spectral type: G0 D
> V 9.1
>
> The secondary is of V 9.75 but is not listed in SIMBAD.
> The Separation A-B is just 10.5 arc-seconds making this a reasonably
> close pair to be a genuine binary more than likely!
If I input the position you quote into the Digitized Sky Survey (or
indeed into Vizier) there is indeed a star at the position claimed (it
is TYC 3513-925-1) but there is not - repeat not - another 9.75
magnitude star within 10.5 arc seconds of TYC 3513-925-1.
TYC 3513-925-1 has a large proper motion - look at the PPMX listing.
>
> And the third pair Hercules I am going to have to take another look,
> as I didn't really bother with it after one glimpse:
>
> There is no inclusion of this pair in Washington Double Star catalogue
> and there is no result in SIMBAD either. The only match I could find
> was in Stellarium:
> J2000.0: RA = 18 04 40.3, Dec = +23 57 52.3
> Mags of ~9.5 and ~10.0, separation ~5 arcseconds apart! Both appeared
> slightly reddish. True binary!
> The location is actually very close to the star HP 88528- Hide quoted text -
>
> - Show quoted text -
The well known pair STF2274 is close by but assuming your positions
are accurate then again I cannot find any photographic evidence of the
two close stars you have identified.
Have you actually seen them with your own eyes or are you relying on
planetarium software?
Mike Dworetsky
news:a0459096-a2a3-42e5...@m39g2000yqc.googlegroups.com...
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MD advises:
Take a look at the Aladin Previewer in Simbad. This will give you a POSS II
Sky Survey image (jpg) or 2MASS (fits: needs a fits viewer installed) of a
12.9x12.9 arcmin area around the object. It's a fun tool, try it. You can
even ask for the images of the original POSS I.
Your star is the brightest in the field. Within about 30 arcsec there are 4
other objects a couple of magnitudes fainter of similar brightness to one
another. Your companion is the closest and brightest only by a small
margin, and looks much less red than the bright star. It doesn't look like
anything more than a random grouping of field stars. I see at least 4 or 5
other similar size groups of 4-5 stars of about the same brightness in the
image. You can ask Aladin to give you a colour view (composite of POSS II F
and J plates), and while your primary looks red (well, orange), the
surrounding stars are definitely yellower or white.
There is a neat close asterism of what looks like 5 white stars (white in
this combination = roughly class late A or F?? I'm guessing) maybe 14th mag
(?? uncertain), about 3 min away at about 1 o'clock. I'd love to think that
it is physical, but at this sort of level of brightness such things show up
a lot and are usually random alignments. (One would need a 5-m telescope to
prove otherwise). There is at least one fairly blue 10th mag star in the
field 10 or 11 arcmin away NW.
My best take on this: the secondary you found does not seem to be a physical
companion and is just another field star among many.
comet....@yahoo.co.uk
wrote:
Thank you for checking. My telescope is problematic for seeing
overhead (zenith). This is actually one I glimpse last autumn when the
head of Draco was much off zenith. I did make a diagram of it, but now
its impossible since my tripod stops the tube on 200 EQ mount of my
skywatcher. Impossible for me this time of year.
If your telescope allows, would you mind having a look? :)
The Hercles pair I saw again last night: J2000 18 24 59.6, +16 41
55.5. The secondary is definitely there! I saw it about 23 arcseconds
away at mag 10 to 11. Can you check it in your Digitized Sky Survey
please?
ukastronomy
>
> - Show quoted text -
There are 2 Tycho stars (8.2 and 10) that are about 17 or 18 arc secs
apart but they have very different proper motions so are not linked
physically.
Mike Dworetsky
it.
<comet....@yahoo.co.uk> wrote in message
news:54d3116e-d022-492a...@y17g2000yqn.googlegroups.com...
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MD advises:
Take a look at the Aladin Previewer in Simbad. This will give you a POSS II
Sky Survey image (jpg) or 2MASS (fits: needs a fits viewer installed) of a
12.9x12.9 arcmin area around the object. It's a fun tool, try it. You can
even ask for the images of the original POSS I.
Your star is the brightest in the field. Within about 30 arcsec there are 4
other objects a couple of magnitudes fainter of similar brightness to one
another. Your companion is the closest and brightest only by a small
margin, and looks much less red than the bright star. It doesn't look like
anything more than a random grouping of field stars. I see at least 4 or 5
other similar size groups of 4-5 stars of about the same brightness in the
image. You can ask Aladin to give you a colour view (composite of POSS II F
and J plates), and while your primary looks red (well, orange), the
surrounding stars are definitely yellower or white.
There is a neat close asterism of what looks like 5 white stars (white in
this combination = roughly class late A or F?? I'm guessing) maybe 14th mag
(?? uncertain), about 3 min away at about 1 o'clock. I'd love to think that
it is physical, but at this sort of level of brightness such things show up
a lot and are usually random alignments. (One would need a 5-m telescope to
prove otherwise). There is at least one fairly blue 10th mag star in the
field 10 or 11 arcmin away NW.
My best take on this: the secondary you found does not seem to be a physical
companion and is just another field star among many.
--
Odysseus
"Mike Dworetsky" <plati...@pants.btinternet.com> wrote:
<snip>
> [W]e still attach the names of the discoverers to the Struve,
> Herschel, and Aitken double stars in the various lists, e.g.,
> Struve's discoveries are indicated with a capital sigma and a number.
I tend to think of those more as identifying the catalogue (wherein an
object is indexed by that number) than as cases of objects being named
for their discoverers. No doubt many objects named after somebody
appeared in someone else's list before the "discoverer" called attention
to its unusual or exemplary character. The Herschel &c. designations
seem more personal than e.g. the UGC, named for an institution, let
alone e.g. the NGC & IC, but may or may not comprise actual
"discoveries" of the compiler.
--
Odysseus
Odysseus
"Mike Dworetsky" <plati...@pants.btinternet.com> wrote:
<snip>
> I'm not sure--there may be somewhere an explanation of how stars get into
> Simbad, and I don't think being only in the Guide Star Catalogue is enough,
> so this may be the only source where there are any details at all.
Simbad's sources are listed at
<http://cdsarc.u-strasbg.fr/cats/cats.html>.
--
Odysseus
Mike Dworetsky
news:odysseus1479-at-A1...@news.telus.net...
Simbad has around 2.5 million objects (or is it more now?), the Guide Star
Catalogue about 15 million, so if an object is in the GSC it is far from
obvious that it will be in the Simbad list.
There are various software apps which interrogate the entire GSC, however.
comet....@yahoo.co.uk
>
> - Show quoted text -
Last night was clear again. First pair I jumped to was 95 Herculis!.
Awesome spectacle, near equal brightness, tinted a bluish-green at
first sight. Then I remembered the astronomer Smyth (19th century?),
who said the stars was like 'apple and cherry'. Yummy! stars can be as
satisfying to the belly as to the mind :)
I actually didn't think the colours were that vivid! I sort of think
it was more like "grape and lemon"...the green and red were a bit
washed out to paler shades...
Then I resumed my "undiscovered double stars" quest again and
rechecked a pair I had spotted in Ophuichus, where both stars have
similar proper motion vectors so it seems they may physicaly
connected. primary is at RA=17h 52m 24.4s, dec = +08 34 16.9 (J2000).
SIMBAD lists it as "HD 162792 -- Star". Spectral type: F5, mag 9.54.
Secondary is listed as "BD+08 3520s -- Star", at RA=17h 52m 26.7s,
dec= +8 34 19.8, mag 9.96. If we look at the propper motion and the
error ellipses of each star, they overlap!! I thus believe this is a
genuine "common proper motion" pair and separation is ~34 arcseconds,
so they should qualify for WDS catalogue inclusion...
The question also arises: how accurate are the reported proper motions
in SIMBAD?? Sometimes, if the star has very small proper motion, the
errors seem so large in relation to it, as to appear nonsensical. Also
what does the 3rd number really mean? Example: for the star HD 162792,
Proper Motion = mas/yr: -0.60, -4.80, then error ellipse = [2.30 1.70
89]. the first two numbers (2.30 and 1.70) are the errors in mas/yr in
the proper motions in RA and Dec. What does the "89" signify?
SIMBAD has the
Mike Dworetsky
news:6560b069-390a-4045...@v4g2000vba.googlegroups.com...
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MD has looked at this:
The errors are the major and minor axes of the error ellipse, not the NS/EW
errors (which initially one could think is the case). It is the position
angle of the error ellipse in degrees, so 89 signifies that the major axis
of error ellipse is nearly EW. Probably all the angle data is 0-180 (or
179) for these, since there is no need to specify it in quadrants 3 and 4.
The proper motions of many of the stars [including these] are from the Tycho
Catalogue of about one million stars, which gives magnitudes and proper
motions of rather lower accuracy than Hipparcos, but are far better than
nothing. There is also a two-colour Tycho photometry catalogue. Much of
the date for faint stars like these in Simbad are from Tycho.
The catalogue of proper motions results from a comparison of the
Astrographic Catalogue with Hipparcos data. The photometry comes from
Hipparcos raw data, I'm pretty sure.
The spectral class (from the HD Catalogue) is F5 for the first star. The
colour image from POSS II via Aladin Previewer shows the East companion to
be very red. I suspect (if the "D" designation for dwarf is correct) that
they are unlikely to be physically connected. If the red star is a giant,
then it ought to have started with more mass than the F5, and be much more
luminous now. If it is a dwarf, then it is far too bright compared to an F5
main sequence star.
And Simbad provides some multi-waveband photometry for BD +08 3520 that
indicates dwarf, not giant.
The F5 is at d ~330 pc, the M star at maybe 20 pc, if we accept the
photometry.
comet....@yahoo.co.uk
>
> - Show quoted text -
I respect your analysis.
The two stars share very similar proper motions and are more alike,
compared to the famous binary Albireo (Beta Cygni) of separation also
34 arc-seconds, and red + blue/green colours. Albireo's components are
clearly unconnected both by distance/parallax, colours/evolutionary
stages and they also have diverging proper motion vectors.
Interesting,, they are included in WDS catalogue! :)
I believe this HD 162792 / BD+08 3520s pair I just reported is more
deserving to be included in a double star listing as extensive as
WDS...
Mike Dworetsky
news:71a31d4f-3d63-4abe...@n4g2000vba.googlegroups.com...
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Albireo, however, satisfies the Aitken criterion log (rho) < 2.6 -0.2 m,
where for Albireo m is about 3, so rho is around 100 arcsec, which may be
interpreted as saying the physical pairing is probably real if actual rho is
34 arcsec. For your pair, rho is about 5 arcsec, but the separation is
around 34 arcsec, so it is unlikely to be a physical pair. CPM isn't enough
when the proper motions are both within the values of the error ellipses.
I'm not sure where you get your figures for parallax and PM for Albireo.
Simbad lists 8.46 and 8.67 mas for the two components, agreement well within
the errors; the radial velocities are a few km/sec different, but the error
on one of them is 5 km/s, about the same as the difference; the proper
motions are slightly different, which may indicate they are not a physical
pair.
The K3 II giant primary is actually itself double, but the spectral class
quoted in Wikipedia (B0V) is clearly wrong for Mv = 0.46; this would be more
like a B9V. The source seems to be the Washington Catalogue, but where they
got it I do not know. I took spectra myself many years ago and it looked to
me like the close companion was late B. Evolutionary tracks can fit those
parameters reasonably well (distant B has Mv = -0.2). The proper motion
difference may mean they are not truly bound as a pair/multiple system, I
don't know, but the other data either confirm the possibility or are
"neutral".
comet....@yahoo.co.uk
> The two stars share very similar proper motions and are more alike,
> compared to the famous binary Albireo (Beta Cygni) of separation also
> 34 arc-seconds, and red + blue/green colours. Albireo's components are
> clearly unconnected both by distance/parallax, colours/evolutionary
> stages and they also have diverging proper motion vectors.
> Interesting,, they are included in WDS catalogue! :)
>
> I believe this HD 162792 / BD+08 3520s pair I just reported is more
> deserving to be included in a double star listing as extensive as
> WDS...
>
> Albireo, however, satisfies the Aitken criterion log (rho) < 2.6 -0.2 m,
> where for Albireo m is about 3, so rho is around 100 arcsec, which may be
> interpreted as saying the physical pairing is probably real if actual rho is
> 34 arcsec. For your pair, rho is about 5 arcsec, but the separation is
> around 34 arcsec, so it is unlikely to be a physical pair. CPM isn't enough
> when the proper motions are both within the values of the error ellipses.
>
> I'm not sure where you get your figures for parallax and PM for Albireo.
> Simbad lists 8.46 and 8.67 mas for the two components, agreement well within
> the errors; the radial velocities are a few km/sec different, but the error
> on one of them is 5 km/s, about the same as the difference; the proper
> motions are slightly different, which may indicate they are not a physical
> pair.
>
> The K3 II giant primary is actually itself double, but the spectral class
> quoted in Wikipedia (B0V) is clearly wrong for Mv = 0.46; this would be more
> like a B9V. The source seems to be the Washington Catalogue, but where they
> got it I do not know. I took spectra myself many years ago and it looked to
> me like the close companion was late B. Evolutionary tracks can fit those
> parameters reasonably well (distant B has Mv = -0.2). The proper motion
> difference may mean they are not truly bound as a pair/multiple system, I
> don't know, but the other data either confirm the possibility or are
> "neutral".
>
> --
> Mike Dworetsky
>
> (Remove pants sp*mbl*ck to reply)
The Aitken criteria is of course only the very loose and arbitrary
guide - BUT - we do of course need some sensible criteria, otherwise
every star would be said to be a companion to every other! After all,
Newton's gravity equation F=Gm1m2/r^2 dictates that gravity is
infinite in its reach... but let's not go there :)
Consider the pair at RA 18 51 31.79, Dec +101849.8 of 9th and 10th
magnitude stars, separted by 21 arcseconds - waaay outside the Aitken
criteria of only 5 or 6 arcseconds. That pair, nonetheless, IS
INCLUDED in the Washington Double Star catalgue.
Finally, I wanted to ask you about my most likely binary pairing
discovery of all that I have drawn here:
http://uk.geocities.com/aa_spaceagent/Double-Stars.html
"Another promising pair I believe to be a TRUE BINARY is in Vulpecula
(my sketch from last autumn):
http://www.freewebs.com/aa_spaceagent1/ahad_vulpecula_FOVsketch.JPG
This too is not in Washington Double Star catalogue as of May 2009.
So
at a 22" (22 arc-second) separation and almost equal mags at ~10th
magnitude each star, and sharing common proper motion, this is a good
double to add on !
SIMBAD lists the primary at RA 19h 39m 57.7s, DEC +23 17 25.1, of HD
344698.
Proper motion for this star at ~ 6 mas/yr is not vastly different
from
Albireo's (another well-known binary of much visual spectacle) ~ 7
mas/
yr. This suggests the Vulpecula binary pair is not as far away as
their faint (10th magnitude) apparent brightness would suggest. "
Do you think this is a genuine binary or not? The stars are very
equal
in luminosity and spectral class, flyinng through space very happily
together at just 22" apart. Their proper motion is similar to
Albireo's, though of course we have no direct parallax to gauge their
distance from us.
I recommend this be added to WDS catalogue...
Mike Dworetsky
news:3edaa176-481e-4168...@x6g2000vbg.googlegroups.com...
http://uk.geocities.com/aa_spaceagent/Double-Stars.html
-------------------------------------------------------------------------
MD:
The pair is well outside the Aitken limit, but they are two similar stars of
similar brightness. The proper motion accuracy, of course, is much poorer
than that for Albireo. Binarity is conceivable but I don't know how you
could prove it except with some intensive observation with a large
telescope.
oriel36
You are such strange people -
"Cor. 2. And since these stars are liable to no sensible parallax from
the annual motion of the earth, they can have no force, because of
their immense distance, to produce any sensible effect in our system.
Not to mention that the fixed stars, every where promiscuously
dispersed in the heavens, by their contrary actions destroy their
mutual actions"
Prop. LXX, Book I. Newton
The proponderence of 'dark' solutions is a consequence of the attempt
by Newton to make planetary orbital dynamics look like terrestrial
ballistics by isolating the solar system.Modern imaging showing a
default orbital geometry by virtue of a star's displacement from the
center could indicate a galactic orbital feature to heliocentric
elliptical geometry -
http://www.rodiehr.de/c_12_vorg_formalhaut_pic_detail.jpg
http://lh3.ggpht.com/_zRiK-WzJR14/SRyoT72falI/AAAAAAAAAP4/NlWUVeBEGbg/s640/HST3.jpg
Sadly,the framework on which Isaac hung his agenda excludes the
possibility of considering compound heliocentric and galactic orbital
motions in influencing planetary orbital dynamics and shape.
Ah,you are having fun with these things and who am I to spoil your
discovery.
ukastronomy
Same old endlessly repeated and mainly meaningless drivel deleted.
Gerald - is it your intention to keep posting to newsgroups where
virtually everybody ignores or abuses you for the rest of your life?
Just wondering!
oriel36
wrote:
Absolutely not !,what can be said of people who are absolutely certain
that the return of a star to a meridian in 23 hours 56 minutes 04
seconds equates to the daily rotation of the Earth through 360 degrees
insofar as consecquitive returns of the same star register double the
figure.No room for anything additional,just a spinning celestial
sphere with the Earth at the center or a rotating Earth at the center
of a stationary celestial sphere.
The biggest insult I have received is that nobody else has spotted the
same thing,the original conclusion which Flamsteed drew in using
timekeeping averages to determine planetary dynamics and especially
daily rotation is pretty much a catastrophe,making it worse,by
creating a 'sidereal time vs solar time' hoax that obscures the
original relationship between the timekeeping average of the 24 hour
day based on the difference between natural noon and 24 hour noon.
The insults I can handle,as far as I'm concerned you are welcome to
the astrological Ra/Dec convenience,it is the implications for the
rest of science that are shocking and especially the ability to make
observations fit conclusions - think carbon dioxide/global warming as
an extension of the Flamsteed/Newton distortions.
If you find yourself looking at a star in the same position after 47
hours 52 min 08 sec,and indeed you will,the last conclusion you will
draw is that the Earth has rotated through 720 degrees or twice in
that period,you may not know it,but others should.
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
> <comet.see...@yahoo.co.uk> wrote in message
>
> - Show quoted text -
The Aitken criterion obviously takes no account of distance of the
binary from Earth or the intrinsic luminosities of its component
stars. For example, a nearby red dwarf pair of say 8th or 9th
maganitude, separated by a vast angular distance (rho) of say 100 arc-
seconds would fall far outside such a criterion.
Another pair I identified is in Cepheus. Again, it has not been
included as a double star in the WDS catalogue.
The stars HP 104969 (V mag 7.91) and BD+67 1298 (V mag 9.35) in
Cepheus, with an angular separation (rho) of 53.5 arc-seconds are a
100% common proper motion (CPM) pair! They share exactly the same
proper motions of ~49 mas/year, and are separated by 53.5" (53.5 arc-
seconds). SIMBAD data confirms this as follows:
Primary: HIP 104969 (A component)
===========================
ICRS coord. (ep=2000) : 21 15 42.5997 +68 21 07.704
Proper motions mas/yr 12.74 -47.79
PM error ellipse: [0.65 0.62 110]
Radial velocity / Redshift / cz : km/s -5.2 [9.5]
Parallaxes mas: 13.31 [0.67]
Spectral type: F0
V 7.91
Secondary: BD+67 1298 (B component)
==============================
ICRS coord. (ep=2000) : 21 15 39.1621 +68 21 23.745
Proper motions mas/yr: 13.70 -47.10
PM error ellipse: [3.20 2.60 0]
Spectral type: G5 D
V 9.35
The primary (HP 104969)'s parallax of 0.01331 arc-seconds gives a
distance of 245 light-years from Earth.
This means the pair is about 40% closer to us than Albireo‘s 386 light-
years. Since Albireo has an Aitken limit of ~100 arc-seconds, with its
components belonging to a higher luminosity class on the Hertzsprung-
Russel diagram, having a rho = 34 arc-seconds, then it can be argued
that my Cepheus pair would have an Aitken limit of something similar
to 100 arc-seconds, as they are (a) intrinsically less luminous, and
(b) much closer to us in geocentric distance.
In fact, the linear physical sepration of the two stars in my Cepheus
binary is *exactly* the same as Albireo’s. There are 63,240 AUs in 1
lightyear. Albireo is about 386 light-yers from earth. So the 34” rho
would be equivalent to Tan (34”) * 386 *63240 = 4023 AUs
In the case of the Cepheus binary, HP 104969 / BD+67 1298, the 53.5”
would be equal to Tan (53.5”) * 245 * 63240 = 4019 AUs
Only time can tell if they will eventualy display orbital motion!! I
am going to write to the BAA Double Star group, of which I am a member
regarding this one! :)
Abdul Ahad
ukastronomy
>
> - Show quoted text -
I am afraid that again you seem to be making claims for a pair of
stars that are simply not backed up by the facts.
The Geneva-Copenhagen Survey of the Solar neighbourhood (Holmberg+,
2007) shows that these stars are at different distances (75 v 83 pc)
and are of very different ages (1.6Gyr v 14.9Gyr). They are not a
binary system!
I have not followed this thread too closely but it seems as if
whenever I examine a claim you make it proves to be incorrect or at
best unproven. I think the solution might be for you to check, double
check and triple check your own claims ***using many more sources***
before offering up any more "discoveries" for comment or inspection.
Martin Nicholson
Daventry, UK
comet....@yahoo.co.uk
wrote:
>
> - Show quoted text -
Do you have a link to this survey I can check? Reason for reporting
them here, so they can be rechecked as I dont obviously know every
single source...
ukastronomy
>
> - Show quoted text -
The source is best checked via Vizier
http://archive.ast.cam.ac.uk/viz-bin/VizieR
It is an interesting point that you raise about rechecking
discoveries. You might be surprised how few times any astronomer can
mistakenly claim a "discovery" before any subsequent claims by them
tend to get ignored. You really do need to take on the responsibility
for properly researching all your objects yourself.
comet....@yahoo.co.uk
> It is an interesting point that you raise about rechecking
> discoveries. You might be surprised how few times any astronomer can
> mistakenly claim a "discovery" before any subsequent claims by them
> tend to get ignored. You really do need to take on the responsibility
>
> - Show quoted text -
Like the boy who shouted "Wolf!" ? haha yes, we've all been there :)
I struggle with technology so i cant get into the Vizier link you
supplied, but thank you all the same.
Assuming the two stars are at 75 and 83 pc distances, respectively, as
you state. There is usually a margin of error of +/-5% or +/- 10% in
the parallax. If you deduct 10% from 83 pc (from my binary's B
component) and add 10% (to my binary's A component), you'll see the
two stars are roughly at equal distances from Earth.
As for the age differences... well I'd always take stellar age
calculations with a pinch of salt. I am dubious of this fact more than
any other in stellar astronomy. How do you explain that Sirius A is
still a young star, when its binary partner has long gone through a
full life-cycle and is now extinguished to a white dwarf? Or Procyon
for that matter?
So for my Cepheus pair... the upshot is we have two stars showing 100%
common proper motion match in the direction of their space velocity,
that are roughly at the same distance from us, satisfying similar
criteria to Albireo A and B's "loose" association. I'd say that's
pretty reasonable gounds for listing the star as a binary candidate...
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
> -------------------------------------------------------------------------------
>
> Albireo, however, satisfies the Aitken criterion log (rho) < 2.6 -0.2 m,
> where for Albireo m is about 3, so rho is around 100 arcsec, which may be
> interpreted as saying the physical pairing is probably real if actual rho is
> 34 arcsec. For your pair, rho is about 5 arcsec, but the separation is
> around 34 arcsec, so it is unlikely to be a physical pair. CPM isn't enough
> when the proper motions are both within the values of the error ellipses.
>
> I'm not sure where you get your figures for parallax and PM for Albireo.
> Simbad lists 8.46 and 8.67 mas for the two components,
I think you may have read the wrong row in SIMBAD; it happens to me
very often! Those are actually the Parallax numbers, not the proper
motions.
The proper motion components (RA & Dec) for Albireo A are:
-7.09 -5.63 , error ellipse [0.69 0.48 154]
The proper motion components (RA & Dec) for Albireo B are:
-1.95 -0.98 , error ellipse [0.68 0.49 159]
Those are of course the proper motion resolved in the directions of RA
and Dec. The total proper motions of each star are:
For Albireo A, the net proper motion is sqrt[-7.09^2 + -5.63^2] = 9.05
milliarcseconds/year
For Albireo B, it would be sqrt [-1.95^2 + -0.98^2] = 2.18
milliarcseconds/year
Therefore the two stars are not a true "common proper motion" pair.
> the proper
> motions are slightly different, which may indicate they are not a physical
> pair.
I agree.
Could it however be argued that the differences in proper motion are
due to orbital motion? If the secondary is circling the primary, would
it be moving fast enough for there to be a difference in their proper
motion directions? I think unlikely given the vast thousands of year
orbital periods...
Interesting though!
> Mike Dworetsky
>
dachemist
<platinum...@pants.btinternet.com> wrote:
> "ukastronomy" <martin_piers_nichol...@yahoo.co.uk> wrote in message
>
> news:93128dd4-50ec-421e...@21g2000vbk.googlegroups.com...
>
>
>
> > On May 20, 2:38 pm, "Mike Dworetsky"
> > > Mike Dworetsky
>
> > > (Remove pants sp*mbl*ck to reply)- Hide quoted text -
>
> > > - Show quoted text -
>
> > as true double stars and any physical association is only suspected.
> > I'd just leave it at that for now. They are still pairs I discovered!
>
> > - Show quoted text -
>
> is that although you have discovered nothing of significance you have
> had fun and have learnt something new.
> --------------------------------------------------------------------------- -----
You must be somebody real important real smart
Or just plain have your finger up your ass!
What a conceited prick!
why don't you contribute rather then grace us with your Self eulogy
Do you enshrine ever crap you take?
> I have nothing at all against amateur astronomers enjoying looking at the
> night sky. That's why it's there, isn't it? Just don't read more into the
> observations than is warranted.
>
Androcles
"dachemist" <chemi...@gmail.com> wrote in message
news:cbccaae7-8340-4f9e-87e3-
Wow m I in the presence of greatness here?
You must be somebody real important real smart
Or just plain have your finger up your ass!
What a conceited prick!
why don't you contribute rather then grace us with your Self eulogy
Do you enshrine ever crap you take?
Wow, am I in the presence of smallness here?
You must be nobody of any importance real stooopid
Or just plain have your nose up your arse!
What a conceited miserable cunt!
Why dont you fuck off?
*plonk*
Do not reply to this generic message, it was automatically generated;
you have been kill-filed, either for being boringly stupid, repetitive,
unfunny, ineducable, repeatedly posting politics, religion or off-topic
subjects to a sci. newsgroup, attempting cheapskate free advertising
for profit, because you are a troll, simply insane or any combination
or permutation of the aforementioned reasons; any reply will go unread.
Boringly stupid is the most common cause of kill-filing, but because
this message is generic the other reasons have been included. You are
left to decide which is most applicable to you.
There is no appeal, I have despotic power over whom I will electronically
admit into my home and you do not qualify as a reasonable person I would
wish to converse with or even poke fun at. Some weirdoes are not kill-
filed, they amuse me and I retain them for their entertainment value
as I would any chicken with two heads, either one of which enables the
dumb bird to scratch dirt, step back, look down, step forward to the
same spot and repeat the process eternally.
This should not trouble you, many of those plonked find it a blessing
that they are not required to think and can persist in their bigotry
or crackpot theories without challenge.
You have the right to free speech, I have the right not to listen. The
kill-file will be cleared annually with spring cleaning or whenever I
purchase a new computer or hard drive.
I hope you find this explanation is satisfactory but even if you don't,
damnly my frank, I don't give a dear. Have a nice day.
Mike Dworetsky
news:ca2e156b-55ba-4a1d...@s28g2000vbp.googlegroups.com...
I agree.
--------------------------------------------------------------------------------------------
Thank you, I am aware that I was reading the Albireo parallaxes, which are
nearly the same for both components (and the same within measurement
errors). Perhaps I was not clear enough about this. Yes, the proper
motions are different, which I acknowledged above, but possibly not enough
to rule out physical binarity. My other comment was about the fact that
there seems to be an error, somewhere, in the spectral type attributed to
the secondary of component of A. It can't be a B0V; it might be a B9V. In
fact the three stars (Aa, Ab, and B) would fit an HR diagram pretty well, as
a coeval set of stars.
Mike Dworetsky
news:ca2e156b-55ba-4a1d...@s28g2000vbp.googlegroups.com...
I agree.
--------------------------------------------------------------------------------
This may be possible. Simplest naive calculation:
Separation is 35 arcsec x 130 pc distance, so about 4500 AU if both are in
the plane of the sky. Total mass roughly 10 Msun. Kepler's third law gives
M P^2 = a^3 or P = (roughly) 95,500 years. (Could be less if the masses are
a bit higher)
Assume for simplicity a circular orbit of B around A with rho 35 arcsec.
Circumference is 2pi times 35 so 220 arcsec. Proper motion difference is
around 6.5 mas/yr, or 1 arcsec evey 154 years. 154 x 220 = 34000 yr, very
roughly.
Now I haven't worked out any vectors, because the data are insufficient, but
by a factor of 3 the pm is a bit faster than one might expect for a bound
orbit, but any of the assumptions above (such as circular orbit in the plane
of the sky) could be wrong. So it is at least plausible (but not confirmed)
that they are gravitationally bound.
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
>
> This may be possible. Simplest naive calculation:
>
> Separation is 35 arcsec x 130 pc distance, so about 4500 AU if both are in
> the plane of the sky. Total mass roughly 10 Msun. Kepler's third law gives
>
> M P^2 = a^3 or P = (roughly) 95,500 years. (Could be less if the masses are
> a bit higher)
>
> Assume for simplicity a circular orbit of B around A with rho 35 arcsec.
> Circumference is 2pi times 35 so 220 arcsec. Proper motion difference is
> around 6.5 mas/yr, or 1 arcsec evey 154 years. 154 x 220 = 34000 yr, very
> roughly.
>
> Now I haven't worked out any vectors, because the data are insufficient, but
> by a factor of 3 the pm is a bit faster than one might expect for a bound
> orbit, but any of the assumptions above (such as circular orbit in the plane
> of the sky) could be wrong. So it is at least plausible (but not confirmed)
> that they are gravitationally bound.
>
> --
> Mike Dworetsky
>
> (Remove pants sp*mbl*ck to reply)
That's a really interesting way of analysing! I'll be sure to repeat
similar calculation for each of the pairs I've identified. Having
sifted through my list, I have narrowed to these 4 pairs that are
genuinely CPM and from what data I have, they seem worthy of further
investigations:
(1) In Lacerta
Primary: HD 213128 -- Star (A component)
========================================
ICRS coord. (ep=2000) : 22 28 13.7025 +51 54 19.833
Proper motions mas/yr [error ellipse]: -2.60 0.50
Error ellipse: [1.70 1.60 90]
Spectral type: A0 D
V 8.88
Secondary: BD+51 3386 -- Star (B component)
===========================================
ICRS coord. (ep=2000) : 22 28 15.8443 +51 54 39.408
Proper motions mas/yr [error ellipse]: -3.90 1.30
Error ellipse: [1.80 1.70 90]
Spectral type: A0 D ~
V 9.88
Rho is between 30 and 40 seconds of arc
(2) In Vulpecula
Primary: HD 344698 (A component)
========================================
ICRS coord. (ep=2000) : 19 39 57.6679 +23 17 25.165
Proper motions mas/yr: 5.20 -4.40
Error ellipse: [1.80 1.70 179]
Spectral type: A7 D
V Mag: 10.01
Secondary: HD 344697 (B component)
========================================
ICRS coord. (ep=2000) : 19 39 56.2687 +23 17 34.312
Proper motions mas/yr : 5.90 -3.70
Error ellipse : [1.80 1.70 90]
Spectral type : A7 D
V Mag : 10.18
Rho is ~ 22 seconds of arc
(3) In Cepheus
Primary: HD 344698 (A component)
========================================
ICRS coord. (ep=2000) : 19 39 57.6679 +23 17 25.165
Proper motions mas/yr: 5.20 -4.40
Error ellipse: [1.80 1.70 179]
Spectral type: A7 D
V Mag: 10.01
Secondary: HD 344697 (B component)
========================================
ICRS coord. (ep=2000) : 19 39 56.2687 +23 17 34.312
Proper motions mas/yr : 5.90 -3.70
Error ellipse : [1.80 1.70 90]
Spectral type : A7 D
V Mag : 10.18
Rho is around 53.5 seconds of arc
(4) In Hercules
Primary: BD+36 3014 (A component)
======================================
ICRS coord. (ep=2000) : 18 05 36.2030 +36 18 04.863
Proper motions mas/yr: -6.10 -11.40
Error ellipse: [6.50 2.10 90]
Spectral type: F2 D
V Mag: 9.44
Secondary: BD+36 3014p (B component)
========================================
ICRS coord. (ep=2000) : 18 05 32.9767 +36 18 10.551
Proper motions mas/yr : -12.10 -16.50
Error ellipse : [4.80 1.60 89]
Spectral type : K0 D
V Mag : 10.16
Rho is ~48 seconds of arc
Question:- Is there any old photografic survey going back to 1920s or
older that could be used to check if there is minute chang in sky
position of each star, I wonder? The POSS images I obtained from
aladdin previews must be quite recent, I posted some image files on
here:
http://uk.geocities.com/aa_spaceagent/Double-Stars.html
cheers,
Abdul Ahad
Mike Dworetsky
news:e6fe06c4-42c8-4977...@f16g2000vbf.googlegroups.com...
(1) In Lacerta
(2) In Vulpecula
(3) In Cepheus
(4) In Hercules
http://uk.geocities.com/aa_spaceagent/Double-Stars.html
cheers,
Abdul Ahad
--------------------------------------------------------------------------------------
MD
POSS I was in c. 1950-52; POSS II in the later 1970s. Each plate should
have the exact date noted. I think there are other web based sources for
the POSS and ESO and AAO plates digitised (the latter two for southern sky).
ukastronomy
I cannot anything here or in additional sources available via Vizier
that would make me think that any of these pairs are showing Common
Proper Motion.
There are planty of CPM bianry stars in the sky that don't appear in
WDS so refine your methodology! Find a way to access Vizier as your
starting point.
http://vizier.ast.cam.ac.uk/viz-bin/VizieR
>
> (1) In Lacerta
>
> Primary: HD 213128 -- Star (A component)
> ========================================
> ICRS coord. (ep=2000) : 22 28 13.7025 +51 54 19.833
> Proper motions mas/yr [error ellipse]: -2.60 0.50
> Error ellipse: [1.70 1.60 90]
> Spectral type: A0 D
> V 8.88
>
> Secondary: BD+51 3386 -- Star (B component)
> ===========================================
> ICRS coord. (ep=2000) : 22 28 15.8443 +51 54 39.408
> Proper motions mas/yr [error ellipse]: -3.90 1.30
> Error ellipse: [1.80 1.70 90]
> Spectral type: A0 D ~
> V 9.88
>
> Rho is between 30 and 40 seconds of arc
Nothing in the various catalogues available via Vizier that would make
me give this "pair" a second look.
>
> (2) In Vulpecula
>
> Primary: HD 344698 (A component)
> ========================================
> ICRS coord. (ep=2000) : 19 39 57.6679 +23 17 25.165
> Proper motions mas/yr: 5.20 -4.40
> Error ellipse: [1.80 1.70 179]
> Spectral type: A7 D
> V Mag: 10.01
>
> Secondary: HD 344697 (B component)
> ========================================
> ICRS coord. (ep=2000) : 19 39 56.2687 +23 17 34.312
> Proper motions mas/yr : 5.90 -3.70
> Error ellipse : [1.80 1.70 90]
> Spectral type : A7 D
> V Mag : 10.18
>
> Rho is ~ 22 seconds of arc
Nothing in the various catalogues available via Vizier that would make
me give this "pair" a second look.
>
> (3) In Cepheus
>
> Primary: HD 344698 (A component)
> ========================================
> ICRS coord. (ep=2000) : 19 39 57.6679 +23 17 25.165
> Proper motions mas/yr: 5.20 -4.40
> Error ellipse: [1.80 1.70 179]
> Spectral type: A7 D
> V Mag: 10.01
>
> Secondary: HD 344697 (B component)
> ========================================
> ICRS coord. (ep=2000) : 19 39 56.2687 +23 17 34.312
> Proper motions mas/yr : 5.90 -3.70
> Error ellipse : [1.80 1.70 90]
> Spectral type : A7 D
> V Mag : 10.18
>
> Rho is around 53.5 seconds of arc
Nothing in the various catalogues available via Vizier that would make
me give this "pair" a second look.
>
> (4) In Hercules
>
> Primary: BD+36 3014 (A component)
> ======================================
> ICRS coord. (ep=2000) : 18 05 36.2030 +36 18 04.863
> Proper motions mas/yr: -6.10 -11.40
> Error ellipse: [6.50 2.10 90]
> Spectral type: F2 D
> V Mag: 9.44
>
> Secondary: BD+36 3014p (B component)
> ========================================
> ICRS coord. (ep=2000) : 18 05 32.9767 +36 18 10.551
> Proper motions mas/yr : -12.10 -16.50
> Error ellipse : [4.80 1.60 89]
> Spectral type : K0 D
> V Mag : 10.16
>
> Rho is ~48 seconds of arc
>
Nothing in the various catalogues available via Vizier that would make
me give this "pair" a second look.
Mike Dworetsky
POSS I dates: 1950-57
POSS II dates: "1980s" to 1999.
Links to the surveys:
http://www.astro.caltech.edu/~wws/poss2.html
The digital versions are provided by the Space Telescope Science Institute.
http://archive.stsci.edu/cgi-bin/dss_form
I'm not sure how you interrogate the database for the date of an image, but
it should be possible somehow.
comet....@yahoo.co.uk
Thank you, those links are pretty useful!
In an earlier post on this thread I said I discovered a 10.5-11-ish
magnitude companion to the 8th magnitude red star BD+16 3495 in
Hercules:
http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
If we now compare the POSS I image of this star goin back to 1950s:
http://tinyurl.com/pbh5xq against the POSS II image plate in the
1990s: http://tinyurl.com/pklvqp
We note that the secondary companion has shifted closer toward the
primary by a significant margin (1950's vs 1990s)!! Could this be due
to orbital motion? Or is it a high proper motion foreground star that
is simply passing BD+16 3495 due to our line of sight?!
Mike Dworetsky
news:3b732331-d224-4295...@t10g2000vbg.googlegroups.com...
---------------------------------------------------------------------------------------
Well spotted. Probably the latter, given that it has moved wrt the brighter
star and the other 3 faint background objects. That would be an incredible
amount of orbital motion for only 30-40 years, for such a large separation.
Possibly it is a high proper motion background star, given its faintness.
Could be a halo star (which often have very high pm and RV compared to disk
population)? +16 3495 has a relatively small proper motion as previously
noted. If it is a true M0 V as Simbad suggests with M0 D, then it must be
only a few parsecs away.
dachemist
Visual doubles in the optical field
Binary star - consisting of two ( or more stars) who share a mutual
orbit and exist physically at a similar distance
Visual doubles are typically something that have some close proximity
presumably less than an arc minute
Somewhere nearer to less than 30" arc
The probability that two stars appear close is of interest to visual
observing and gauging field of view
Of greater significance is the discovery of a true binary system
Here the tools necessary to better determine their authenticity would
be to first establish if they are the same distance presumably via red
shift
Certainly there are spectral criteria that will assist an individual
Along with longer term observations to vector in their proper motions
and center of gravity
These are far beyond many amatuers capabilities so I would defer to a
professional astronomer or contact the web society for double stArs
observTions
They would help one with methods as to how to determine these
Parameters in the meantime I will look into this out of curiosity
comet....@yahoo.co.uk
<platinum...@pants.btinternet.com> wrote:
>
> Thank you, those links are pretty useful!
> In an earlier post on this thread I said I discovered a 10.5-11-ish
> magnitude companion to the 8th magnitude red star BD+16 3495 in
> Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
> If we now compare the POSS I image of this star goin back to 1950s:http://tinyurl.com/pbh5xqagainst the POSS II image plate in the
> 1990s:http://tinyurl.com/pklvqp
> We note that the secondary companion has shifted closer toward the
> primary by a significant margin (1950's vs 1990s)!! Could this be due
> to orbital motion? Or is it a high proper motion foreground star that
> is simply passing BD+16 3495 due to our line of sight?!
>
> ---------------------------------------------------------------------------------------
>
> Well spotted. Probably the latter, given that it has moved wrt the brighter
> star and the other 3 faint background objects. That would be an incredible
> amount of orbital motion for only 30-40 years, for such a large separation.
> Possibly it is a high proper motion background star, given its faintness.
> Could be a halo star (which often have very high pm and RV compared to disk
> population)? +16 3495 has a relatively small proper motion as previously
> noted. If it is a true M0 V as Simbad suggests with M0 D, then it must be
> only a few parsecs away.
>
> --
> Mike Dworetsky
>
> (Remove pants sp*mbl*ck to reply)- Hide quoted text -
>
> - Show quoted text -
Sounds plausible.
We cannot rule out binarity entirely, however.
Consider the binary star 61 Cygni, consisting of a pair of red dwarfs,
somewhat similar to BD+16 3495 and just a few parsecs away from us.
Angular separation (rho) is ~30 arc-seconds and the orbital period (P)
is ~650 years. If we assume a circular orbit in the plane of the sky,
then the full orbit circumference would be 2 * Pi * 30 = 188 arc-
seconds.
In the 40 year interval between POSS I and POSS II surveys, we expect
the secondary star to travel (40/650 * 188 = ~ 12 arc-seconds.
This appears to be the sort of angular distance that the secondary
star in my BD+16 3495 pair has covered between 1950s and 1990s (POSS I
& II).
The other interesting thing to note is the match in red coloration of
both stars in the pair; red dwarf binaries seem to occur in relative
abundance for some reason in the Solar neighborhood, e.g. Groombridge
34 A/B, Kruger 60 A/B, 61 Cygni A/B, Struve 2398 A/B, etc.
Abdul Ahad
dachemist
Visual binaries - components of these systems physically related
Careful observation required to establish their center of gravity over
Years to ascertain orbit
Optical double - most likely what u "discovered" a coincidental
optical
Alignent of stars in a telescope - most if not all are associated at
or less than
5" separation
Spectroscopic binaries - self explanatory
Webb society can be accessed on the Internet
PAIR TO THE LEFT OF HP63952:
>
> RA 13h 06m 23.2s, Dec +62deg 01min 08.6arcsec (magnitude
> about 8.9)
>
> RA 13h 06m 24.7s, Dec +62deg 00min 53.4arcsec (mag about
> 9.8)
>
> Separation of approx 25" (25 arc-seconds)
>
> They are fairly wide, but the stars are reddish in colour, so my guess
> is they are red dwarfs and may be not too far away in distance, making
> them appear wider in separation...
hb
newvar...@hushmail.com
wrote:
Strong words from the man who found lots of stars that just happened
to be next to each other in the 2MASS catalogues and had no proper
motion information available, but claimed them as hundreds and
hundreds of doubles, and then declared himself to be the greatest
binary star astronomer since the Struves, yet didn't even know what
common proper motion was until he saw others use it. Oh, I forget the
hilarious one where he wrote to the editors of the Monthly Notices of
the Astronomical Society claiming a paper used all wrong data, but he
had to write to them to withdraw his complaint when it turned out that
VizieR used RA cosine (declination) corrections, whereas the paper
used the original source catalogue, which did not, and because he know
nothing of proper motion, he didn't understand this.
But by all means, take this testimonial to his credentials as the
great double star expert, as expressed in his own press release,
written about himself by himself
http://stupendous.rit.edu/tass/mailarchive/2003-06/msg00147.html
newvar...@hushmail.com
> On May 28, 1:31 pm, "Mike Dworetsky"
>
>
>
> <platinum...@pants.btinternet.com> wrote:
>
> > Thank you, those links are pretty useful!
> > In an earlier post on this thread I said I discovered a 10.5-11-ish
> > magnitude companion to the 8th magnitude red star BD+16 3495 in
> > Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
Hiya
Look, you can't make things be because you want them to be, you've got
to have some data.
Now, the red star that moves is in the Tycho catalogue and has a
proper motion logged for it. The brighter star, the BD star, also has
a proper motion in that catalogue.
Now, even if somehow this was one of the nearest stars to us and the
fact had been missed, what you say still cannot work, because even if
there was relative motion due orbital motion, both stars would have
very similar proper motions as they would also be moving through space
together if they were a gravitationally bound pair. For the fainter
star to be in orbit about the brighter star, both stars have to be in
motion together as well through space, one cannot leave the other
behind.
And the proper motions of the two stars are quite distinct.
The brighter star is classed as spectral type M0, shows no proper
motion to speak of, probably a moderately distant red giant. The
moved star appears to be somewhat red but not greatly so, might be a
foreground red dwarf (from the proper motion), might be a foreground K
dwarf, in fact a G dwarf isn't impossible either. That would lead to
a far bigger magnitude difference than actually exists for the pair.
But that last paragraph itself is speculative, based on unclear data.
What is clear is the object that is BD etc has moved little if any at
all since being photographed in 1898, whilst the other has moved about
13 arcseconds since being photographed in 1898.
In your 61 Cygni example, if you look into it, you will find that that
has not only had motion of one star about the other (actually 61 Cygni
is one of those fast enough and close enough that people can actually
calculate that both stars are moving around a barycentre and solve for
that, not one star around the other) but 61 Cygni has also has both
stars moving in space with proper motion.
You cannot make two stars be binaries without a fair amount of
evidence, and even then only the ones with orbital solutions are very
safe. Common proper motion pairs exist too, which of these are
binaries and which are common proper motion and which are just joint
members of moving streams, all are overlap and borderline type areas.
comet....@yahoo.co.uk
> On May 28, 10:50 pm, comet.see...@yahoo.co.uk wrote:
>
>
>
>
>
> > On May 28, 1:31 pm, "Mike Dworetsky"
>
> > <platinum...@pants.btinternet.com> wrote:
>
> > > Thank you, those links are pretty useful!
> > > In an earlier post on this thread I said I discovered a 10.5-11-ish
> > > magnitude companion to the 8th magnitude red star BD+16 3495 in
> > > Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
>
> - Show quoted text -
You're right. We do need more data to confirm or deny if this is a
genuine binary pair or simply a foreground vs background stellar
alignment. The specific data we need is *parallax*. For both stars.
Does Tycho catalog list this?
As for the lack of moton of primary across the sky, suppose if all the
motion of this star was directed along its radial velocity line? So
that it appears stationary in the sky, with no tangential component to
its PM? In that case, we would have exactly the kind of scenario which
we are seeing, where we see the primary stationary in the middle, with
the secondary moving about it much like in this diagram:
http://www.dibonsmith.com/cyg_del.gif
comet....@yahoo.co.uk
>
>
>
>
>
> > On May 28, 1:31 pm, "Mike Dworetsky"
>
> > <platinum...@pants.btinternet.com> wrote:
>
> > > Thank you, those links are pretty useful!
> > > In an earlier post on this thread I said I discovered a 10.5-11-ish
> > > magnitude companion to the 8th magnitude red star BD+16 3495 in
> > > Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
>
> - Show quoted text -
The other point you mentioned is the secondary has moved about 13
arcseconds since being photographed in 1898. So if we have
photographs
taken in 1898, 1950s and 1990s (the last two in the POSS
surveys)..can
we duduce if the motion has been in a straight line or a curve? If
the
movements are non-linear, then that would be indicative of orbital
motion. If the motion is a perfect straight line, then this would
rule
out elliptical orbital motion.
Greg Hennessy
> You're right. We do need more data to confirm or deny if this is a
> genuine binary pair or simply a foreground vs background stellar
> alignment. The specific data we need is *parallax*. For both stars.
> Does Tycho catalog list this?
Not in general. While Hipparcos stars (which have a measured parallax
and parallax error) that are just in the Tycho catalog obviously have
parallaxes, the Tycho stars don't have measured parallaxes.
badastrobuster
Could this be the John Greaves who has called many of his own
published double star results "totally spurious"? Err, yes it could.
Did he then do anything about correcting them - err, no he didn't.
Actually John knows quite well that the complaint lodged with the RPS
was not withdrawn. I raised concerns about his methodology (hence his
subsequent shamefaced admission about hundreds of spurious claims) at
which point my involvement ended.
Mike Dworetsky
news:1ae12369-928c-4a69...@h23g2000vbc.googlegroups.com...
http://www.dibonsmith.com/cyg_del.gif
--------------------------------------------------------------------------------------
The point being made is that a claim of a *possible* wide binary is all very
well, but without solid proof of a physical connection (either via proximity
statistics, such as Aitken's criterion, or by measured common proper motion,
radial velocity and parallax), it is better to hold such a claim in abeyance
until that evidence exists.
The catalogues of variable stars are full of suspected variables that turned
out to be dubious observations rather than genuine discoveries. So it is
better for the science to be conservative about such things, otherwise we
would all spend too much time investigating phantoms.
None of this should stop you from pursuing your own investigations, but
trying to get them into a big catalogue (Washington Double Star Cat) wastes
the time of everyone else. Some day there will be another better
positional/proper motion satellite (a sort of Hipparcos II), or an improved
hybrid of ground-based/space-based data frames, which may resolve these
matters. Until then, we just have to be patient.
For example, while what you suggest is physically possible (a nearby star
happens to be aimed straight at us or away from us) but unlikely. And the
rate of motion of the secondary of your "binary" is so high as to make it
unlikely that the two are connected.
No, Tycho Catalogue does not list parallax unless the star was also in the
Hipparcos Catalogue, though I believe it lists proper motion (derived from
the Astrographic Catalogue, etc in many cases). Tycho was primarily a
photometry exercise for fainter stars.
Mike Dworetsky
<comet....@yahoo.co.uk> wrote in message
news:4e19eea6-0592-4a77...@p4g2000vba.googlegroups.com...
-----------------------------------------------------------------------------------
The movement could be orbital along a straight line, but you would need to
see acceleration to call it orbital motion. At present there is
insufficient data on the rpoper motion (only three epochs?). My view
remains that this is very unlikely to be a true binary.
newvar...@hushmail.com
> On May 29, 9:39 pm, newvariab...@hushmail.com wrote:
>
>
>
> > On May 28, 10:50 pm, comet.see...@yahoo.co.uk wrote:
>
> > > On May 28, 1:31 pm, "Mike Dworetsky"
>
> > > <platinum...@pants.btinternet.com> wrote:
>
> > > > Thank you, those links are pretty useful!
> > > > In an earlier post on this thread I said I discovered a 10.5-11-ish
> > > > magnitude companion to the 8th magnitude red star BD+16 3495 in
> > > > Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
The WDS double star people have recently started another catalogue
called the Catalogue of Rectilinear Elements or something. It uses
the principles you mention yourself. The motion is not likely to be a
perfect straight line, because measurements aren't perfect, but it
should be straight enough. Given four data points only, you might
decide it is linear, you might decide it is curved. When you have
very little data it is possible to see anything. But yes, with the
positions from several epochs you can manage this. Use VizieR. Use
the positions from the AC2000.2, that will give you 1898.55. POSS I
positions for 1950s, use 2MASS or CMC14 positions for 2000s. If you
can get a POSS II position too, that is fine. And was there a Tycho2
positon too? That gives 1991.25 mean epoch.
You may have to search on the web for Rectilinear Catalogue, most of
the USNO websites have migrated recently.
newvar...@hushmail.com
<platinum...@pants.btinternet.com> wrote:
> <comet.see...@yahoo.co.uk> wrote in message
>
> news:1ae12369-928c-4a69...@h23g2000vbc.googlegroups.com...
> On May 29, 9:39 pm, newvariab...@hushmail.com wrote:
>
>
>
> > On May 28, 10:50 pm, comet.see...@yahoo.co.uk wrote:
>
> > > On May 28, 1:31 pm, "Mike Dworetsky"
>
> > > <platinum...@pants.btinternet.com> wrote:
>
> > > > Thank you, those links are pretty useful!
> > > > In an earlier post on this thread I said I discovered a 10.5-11-ish
> > > > magnitude companion to the 8th magnitude red star BD+16 3495 in
> > > > Hercules:http://www.freewebs.com/aa_spaceagent1/hercules_red_bd+163495_ahad.jpg
>
> > > > If we now compare the POSS I image of this star goin back to
Listen to what this guy has said about your binaries. Well stated,
clearly expressed, no personal inflection or rudeness either intended
or accidentally expressed.
Beware false experts, there are many. You can usually tell the
helpful people by the general tone of their statements and how much
meaningful information they point you towards is.
With the spread of the internet and access to much data there is a
flood of results and possibilities, some real, some simply mistaken,
some false, and some from charlatans, and the system can't keep up.
For you to have a chance of something concrete you have to use a
mindset that makes you as rigorous as possible with as much
information as possible. Just chasing after the same point and making
more and more special circumstances does not add information, it just
adds questions, and it is not a matter of who argues most, it is a
matter of the data.
There are various self advertisers and madmen out there who will
regularly tell everyone how great they are in numerous online
resources, and all their discoveries and findings. You usually find
that they rarely publish, and when they do it is either wrong or
indifferent or borrowed. I am relying on some of them to cause great
harm to some groups who will insist on not protecting themselves
properly from such people despite concrete evidence of specific
instances of strong misconduct being presented. In fact, I will laugh
when it happens.
If you are truly interested the first aspect is to apply some rules
and discipline to the matter. Listen to your own decisions and
statements and decide how you would feel if they were being made to
you by a salesman on your doorstep trying to convince you to part with
money.
This fellow here has given you sound advice, he's not dismissed you
out of hand, he's not been rude or superior just pointing at clever
things and saying he knows better in his infinite experience, he's
given you guidance. That's getting a bit rare nowadays, especially
with the self appointed greats living upon the internet.
Move on from these stars and look elsewhere. Proper motion catalogues
for objects with large proper motions, and reading the Webb Society
Double Star Section Circulars and the Journal of Double Star
Observations, both freely available online, and using the WDS website,
may help you target better.
Be thoughtful in your assessment, however, not all the papers in these
journals are valid. For instance you will see that ukastronomy has
published many "doubles" that readily directly contravene the rules he
applies to yourself in such a discouraging and dismissive manner.
Rules he was unaware of until he saw them used by others, and then
still screwed it up himself half the time, hence why I take offence to
the way he so arrogantly dismisses you.
That is another reason you should listen when someone does give you
good advice, and not try to find ways out by thinking too much and
special pleading. Helpful people are becoming exceedingly rare. Self
glorifying self important dilletantes are becoming the replacement.
Take advantage of the good whilst it still exists.
We cannot make this star into a binary for you. But pointers have
been given to you where instead you can use the energy you are using
to go and look for real binaries.
Interest is good, obsession and fixation can occur if you are not
careful. If things where too easy to find they would have already
been found.
newvar...@hushmail.com
Very small proper motions are about the same size as the real errors
on the proper motions. The real errors can be larger than the quoted
errors. They are usually catalogue dependent.
Try not to match any proper motions of less than +/- 10 mas/y.
Because of errors that is like saying 0 mas/y, and saying 0 is like
saying the star is too far away to see any proper motion, so its
proper motion could be anything.
Some catalogues you shouldn't use any proper motion data of less than
+/- 20 mas/y or even less. mas/y is milliarseconds per year, that is
0.001 arcseconds per year.
It is tricky, there are no concrete rules, and things depend which
data you are using, and many small reasons.
There is a yahoo group called binary stars uncensored. You could try
joining it and asking questions there. However, as with all groups,
this does not necessarily mean you will get any answers. You've had
some good advice here, it seems, amongst other stuff, that may be
enough for you.
But it has to be said that people who insist and insist their stars
are doubles no matter what is said about their candidates will likely
get increasingly less feedback. The same with variable stars, the
same with deepsky objects, the same with many things. There have been
a few around who have made many unfounded claims and they have lowered
the tolerance threshold of the communities towards persistent
viewpoints upon undecidable objects. This is a shame as all beginners
have to find their way and learn from experience what is practical and
what is not scientific due to there not being the information with
which to test the ideas expressed.
Martin Nicholson (NMR)
Just so you all know newvar...@hushmail.com = John Greaves
Could this be the John Greaves who has called many of his own
published double star results "totally spurious"? Err, yes it could.
Did he then do anything about correcting them - err, no he didn't.
Could this also be the John Greaves who wrote as recently as 2008:
"I heartily recommend to all list owners, doing so both now and in the
past, that at best I be strongly moderated, and for full safety's sake
shitlisted (lifetime ban) as this is always the safest with respect to
myself. Filters are good too."
If you publish your results in a newsgroup, in a peer reviewed (or
indeed any) publication or on a web page Greaves will accuse you of
self aggrandisement. If you don't publish your results he will accuse
you of low productivity!
Sometimes, just for variety, he will also claim that :-
Your results are of no interest or value and/or
Your methodology is flawed and/or
You have copied results from somewhere else and/or
Nobody reads (fill in the source) anyway.
Martin Nicholson, Daventry, UK
james
<comet....@yahoo.co.uk> wrote in message
news:ab2c3c4e-1796-4203...@b1g2000vbc.googlegroups.com...
>
> RA 13h 06m 23.2s, Dec +62deg 01min 08.6arcsec (magnitude
> about 8.9)
>
> RA 13h 06m 24.7s, Dec +62deg 00min 53.4arcsec (mag about
> 9.8)
>
> Separation of approx 25" (25 arc-seconds)
>
>
>
> They are fairly wide, but the stars are reddish in colour, so my guess
> is they are red dwarfs and may be not too far away in distance, making
> them appear wider in separation...
>
> optically and mechanicilly inferior . try an english firm like Orion
> optics uk.
they use exellant optic. Or Meade in USA.