Where are those Supernovae?
Dieter Kreuer
I wonder why there has not yet been a posting about a supernova in a nearby
galaxy (I read this newsgroup since last November). As far as I know, there
ought to be a supernova in our milky way galaxy about every 30 years, but the
problem is that we can see just 10 % of it, yielding one SN every 300 years.
But in case of M33, far example, we can see most of the stars, and in the
Andromeda-Galaxy about half of them, I suppose. I own an 8 inch newtonian
reflector. There should be quiet a lot of galaxies within reach of this
instrument. And many of the readers of this newsgroup certainly own or have
access to much larger telescopes. So why are there no SN postings? Or are
SN that boring? I am, however, somewhat envious not having seen SN1987A
(poor northerners...), and hope for another SN1901 in M31. Another Nova Cygni
1975 would also be great (that was just one year before I started sky-gazing).
What about Austin? I saw the comet on April, 27, just before dawn (actually,
dawn had already begun; I had some problems getting out of bed earlier than
4.20).
When I got outside, the sky was amazingly clear and dark, but by the time I
had set up my telescope, it became very rapidly lighter. The comet was fairly
easy to find, but looked very much like a star in my binocs. It was about the
same brightness as M31. Using my 8 inch, it looked like an unresolved globular
cluster with a very bright pinpoint-like center. The coma had a diameter of
about 10 to 15 minutes of arc. I could see no tail, but this was probably due
to the first twilight (and there is also a small town in this direction).
I have not seen too many comets yet (and I own my telescope just since last
November), but this one was certainly the most brilliant to me.
The coordinates of my observing site are 50.8 deg. north, 6.5 deg. east. Our
local time is (due to summer time) GMT + 2 hours.
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Paul Schinder
>
>I wonder why there has not yet been a posting about a supernova in a nearby
>galaxy (I read this newsgroup since last November). As far as I know, there
>ought to be a supernova in our milky way galaxy about every 30 years, but the
>problem is that we can see just 10 % of it, yielding one SN every 300 years.
Be aware that this number is not known with great accuracy. The most
optomistic number I've seen is about 1 every 10 years, and the most
pessimistic about 1 every 200 years. Recent estimates seem to be that
SN are rarer than once thought (i.e. closer to the 1 every 200 year
number).
So long as neutrino detectors remain on line, the most likely way
we'll see the next Galactic supernova (at least Type II) is when 100's
of neutrinos are detected in a burst. In neutrino "light", we can see
the entire Galaxy.
--
Paul J. Schinder
Department of Astronomy, Cornell University
schi...@astrosun.tn.cornell.edu
Philip C. Plait
>I wonder why there has not yet been a posting about a supernova in a nearby
>galaxy (I read this newsgroup since last November).
[...]
>But in case of M33, far example, we can see most of the stars, and in the
>Andromeda-Galaxy about half of them, I suppose. I own an 8 inch newtonian
>reflector. There should be quiet a lot of galaxies within reach of this
>instrument. And many of the readers of this newsgroup certainly own or have
>access to much larger telescopes. So why are there no SN postings? Or are
>SN that boring? I am, however, somewhat envious not having seen SN1987A
>(poor northerners...), and hope for another SN1901 in M31. Another Nova Cygni
>1975 would also be great (that was just one year before I started sky-gazing).
As far as I know, there has only been one SN in M31 since the discovery of
the telescope. This was SN1885a, observed in early (you guessed it) 1885. It
was the first extragalactic SN ever seen. It was located almost on top of the
nucleus of the galaxy (it was a Type I SN, or exploding white dwarf). The fact
that there have been none others observed in 400 years is a bit puzzling.
If you check out the IAU circulars (most Astro departments at universities
get them), you will find that there are ~15-20 SN observed every year, ranging
in magnitude from +3 (two years ago 8-) ) to about +25. Most are at the lowert
end of the scale, found by wide angle SN searches. Very few are brighter than
about +12, a realistic mag limit on an 8" scope.
--
* Phil Plait PC...@bessel.acc.virginia.EDU
* UVa Dept. of Astronomy Grad student (at large)
*
* "Censorship? You're worried about censorship when you write crap like that?"
Rev Phil Skink, DD (Ret.)
pc...@astsun9.astro.Virginia.EDU (Philip C. Plait) writes:
>... Most are at the lower
>end of the scale, found by wide angle SN searches. Very few are brighter than
>about +12, a realistic mag limit on an 8" scope.
Of course, I should point out that the world record holder for
visual SN discoveries (Rev. Robert Evans) uses a 10" newtonian to
eyeball galaxies, and he's found quite few. Many of these discoveries
should be visible in an 8", so all is not lost.
John Kallen
>(poor northerners...), and hope for another SN1901 in M31. Another Nova Cygni
SN1901? Are you perhaps referring to Nova Persei? I have an astronomy
book from 1910 (belonged to my grandfather) and there is a lot of
excited writing about that nova. Don't think it was a supernova,
though.
The remainder of the book is hilarious, especially the chapters
covering the solar system (mind you, this was a very serious book).
The author was all for Schiaparelli's and Lowell's "canals" and flamed
at Antoniadi's observations as being "inferior in quality" and
"careless". Beautiful "artist's impressions" of the lunar surface...
Amazing how much more we know 80 years later (and how much more we
have yet to learn).
_______________________________________________________________________________
| | | | |\ | | /|\ | John Kallen Computer: kom-pyu'-ter (n) a
| |\ \|/ \| * |/ | |/| | | PoBox 11215 device for generating errors
| |\ /|\ |\ * |\ | | | | Stanford CA 94309 speedily and unpredictably.
_|_|___|___|____|_\|___|__|__|_j...@neon.stanford.edu___________________________
Daniel P. Barron
>SN1901? Are you perhaps referring to Nova Persei? I have an astronomy
>book from 1910 (belonged to my grandfather) and there is a lot of
>excited writing about that nova. Don't think it was a supernova,
>though.
>The remainder of the book is hilarious, especially the chapters
>covering the solar system (mind you, this was a very serious book).
>The author was all for Schiaparelli's and Lowell's "canals" and flamed
Sorry to nitpick, but this is an interesting bit of info. If I'm
not mistaken Schiaparellri never said "canals." He used the Italian
"canali" which means, literally, "channels." It was mistranslated and
gave Lowell the ideas of canals of artificial manufacture. "Channels"
does not imply an architect.
Am I right?
Again, sorry to nitpick.
Dan
_______________________________Daniel Barron__________________________________
| E-mail: bar...@wharton.upenn.edu
"Hunger only for a taste of justice, | bar...@eniac.seas.upenn.edu
Hunger only for a word of truth." | bar...@scrolls.wharton.upenn.edu
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T. Joseph Lazio, Cornell University
> In article <1990May9.1...@Neon.Stanford.EDU> j...@Neon.Stanford.EDU (John Kallen) writes:
>>The remainder of the book is hilarious, especially the chapters
>>covering the solar system (mind you, this was a very serious book).
>>The author was all for Schiaparelli's and Lowell's "canals" and flamed
>
> Sorry to nitpick, but this is an interesting bit of info. If I'm
> not mistaken Schiaparellri never said "canals." He used the Italian
> "canali" which means, literally, "channels." It was mistranslated and
> gave Lowell the ideas of canals of artificial manufacture. "Channels"
> does not imply an architect.
>
> Am I right?
Yes.
--
T. Joseph Lazio
Cornell University (607) 255-6420
la...@astrosun.tn.cornell.edu
la...@pulsar.tn.cornell.edu
Joe Dellinger
>I started sky-gazing).
Funny story. In the summer of 1975 I decided to teach myself the constellations
using the star chart in Science News. The FIRST constellation I should learn, I
decided, would be Cygnus. A nice simple cross shape, directly overhead in the
late evening. Should be easy to find!
So I went out with my Science News and tried to find Cygnus. Damn... just
wouldn't work! There was one set of stars that might have matched, except
for an extra bright star that didn't belong. Just couldn't find Cygnus.
Discouraged, I gave up for a few days. About a week later, I got up the
courage to try again. No problem! Then the next issue of Science News
arrives, and talks about how there was this incredibly bright Nova in
Cygnus just for a few nights.... you guessed it.
Now what were the chances of THAT! (It's nice to know on exactly what date
I first started trying to learn astronomy.)
So why hasn't there been another one now that I'd appreciate it!
\ /\ /\ /\/\/\/\/\/\/\.-.-.-.-.......___________
\ / \ / \ /Dept of Geophysics, Stanford University \/\/\.-.-....___
\/ \/ \/Joe Dellinger j...@hanauma.stanford.edu apple!hanauma!joe\/\.-._
************** Drive Friendly, Y'all! ******************************************
David Salzberg
In article <5...@helens.Stanford.EDU> j...@hanauma.stanford.edu (Joe Dellinger) writes:
>In article <28...@rwthinf.UUCP> die...@rwthinf.UUCP (Dieter Kreuer) writes:
->I started sky-gazing).
-
-Funny story. In the summer of 1975 I decided to teach myself the constellations
-using the star chart in Science News. The FIRST constellation I should learn, I
-decided, would be Cygnus. A nice simple cross shape, directly overhead in the
-late evening. Should be easy to find!
-
-So I went out with my Science News and tried to find Cygnus. Damn... just
-wouldn't work! There was one set of stars that might have matched, except
-for an extra bright star that didn't belong. Just couldn't find Cygnus.
-Discouraged, I gave up for a few days. About a week later, I got up the
-courage to try again. No problem! Then the next issue of Science News
-arrives, and talks about how there was this incredibly bright Nova in
-Cygnus just for a few nights.... you guessed it.
-
-Now what were the chances of THAT! (It's nice to know on exactly what date
-I first started trying to learn astronomy.)
-
well, back when I was an undergrad, in the winter quarter of '87, I was
taking a stellar astrophyics coures (my first and only). In late feb.
or early march (I don't remeber exactly), on a tuesday we covered
supernovea. The Prof. mentioned that there had not been a naked eye
subaernovan many years (hundreds comes to mind, but I could be
mistaken). I guess y'all can probably figure out what happened. But for
those that can't, before thursday's class, one of the top news stories
was about a bright (naked eye) supernova... (1987A). The probablility
of that happening to me was:
1 SN/100 years * 1/365 years/day = 1/365000.
I just felt the urge to mention that.
Robert Bunge
discover supernova. I understand he was recently given a 16-inch scope by the
equivalent of the Australian NSF! Gee, could you ever imagine that happening
up here?
Bob Bunge
bu...@osu-20.ircc.ohio-state.edu
Just an amateur staring off into deep space