Planetary Classification System(s)
Willie R. Meghar
this thread as a place to post it.
Here's mine:
A planet is a compact, natural, physical object made of ordinary
matter in orbit about a more massive object or adrift in space. The
eight planetary classes are as follows:
Giant Class: (>= 500 Earth masses & non-fusor)
Jupiter Class: (>= 50 Earth masses < 500 Earth masses)
Neptune Class: (>= 5 Earth masses < 50 Earth masses)
Earth Class: (>= 0.5 Earth masses < 5 Earth masses)
Mars Class: (>= .05 Earth masses < 0.5 Earth masses)
------- Class: (>= .005 Earth masses < .05 Earth masses)
Pluto Class: (>= .0005 Earth masses < .005 Earth masses)
Asteroid Class: (< .0005 Earth masses)
The class between the Pluto and Mars classes can be named for any
object found in that class -- or it could be called the "Vulcan Class"
or anything else the IAU sees fit to call it.
The above system is simple and keeps our solar system reasonably close
to its traditionally accepted form. It allows flexibility in
describing any planetary system. For example, one could refer to all
sun orbiting bodies above the Pluto Class. One could refer to all
Asteroid Class planets simply as "asteroids" or "minor planets" etc.
Willie R. Meghar
RT
politics.
Chris L Peterson
<NoM...@thisaddress.net> wrote:
>Do you have a pet planetary classification system? If so, I offer
>this thread as a place to post it.
I like your concept. I'd revise it, however.
Formally, a planet is [Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, Neptune, Pluto]. Informally a planet could also be any generally
spherical, non-fusing body orbiting a star. This term would never be
used in a scientific publication or situation where rigor was required
(unless referring to the nine planets listed above).
A "planetary body" (or invent your own name) is a non-fusing body
orbiting a star . There are many classifications of planetary bodies. I
wouldn't generally classify by mass, as you have, but by composition and
origin. But the classes could be arbitrarily complex and extendible to
deal with new types of bodies, or new understanding of bodies.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
Thomas Lee Elifritz
Or one could call Ceres an asteroid planet :
http://cosmic.lifeform.org/?p=115
That's still 10 or more planets.
Thomas Lee Elifritz
> Do you have a pet planetary classification system? If so, I offer
> this thread as a place to post it.
>
> Here's mine:
>
> A planet is a compact, natural, physical object made of ordinary
> matter in orbit about a more massive object or adrift in space. The
> eight planetary classes are as follows:
>
> Giant Class: (>= 500 Earth masses & non-fusor)
> Jupiter Class: (>= 50 Earth masses < 500 Earth masses)
> Neptune Class: (>= 5 Earth masses < 50 Earth masses)
> Earth Class: (>= 0.5 Earth masses < 5 Earth masses)
> Mars Class: (>= .05 Earth masses < 0.5 Earth masses)
> Pluto Class: (>= .0005 Earth masses < .005 Earth masses)
> Asteroid Class: (< .0005 Earth masses)
Since we've agreed the scale is arbitrary, I suppose this is as good as
any. The what's his name scale - the Meghar scale of planetary mass
classification, spanning eight full decimal orders of magnitude of
hydrostatic equilibrium. Fortuitously (our solar system is so special)
we have 10 planets at least, two of which are representative of 'belts',
the asteroid belt and the Kuiper Belt, or the trans-Neptunian planets.
Remarkably, we have no lunar class planets, nor any real giants.
I think the idea is to get past the old nine planets thing.
Willie R. Meghar
>I like your concept. I'd revise it, however.
>
>Formally, a planet is [Mercury, Venus, Earth, Mars, Jupiter, Saturn,
>Uranus, Neptune, Pluto]. Informally a planet could also be any generally
>spherical, non-fusing body orbiting a star. This term would never be
>used in a scientific publication or situation where rigor was required
>(unless referring to the nine planets listed above).
>
>A "planetary body" (or invent your own name) is a non-fusing body
>orbiting a star . There are many classifications of planetary bodies. I
>wouldn't generally classify by mass, as you have, but by composition and
>origin. But the classes could be arbitrarily complex and extendible to
>deal with new types of bodies, or new understanding of bodies.
Mass tends to be one of the first physical characteristics known about
newly discovered planetary bodies, whether those bodies be in our own
solar system or in orbit around stars other than our sun. IMO any new
classification system ought to be applicable not only to known
planetary bodies within our own solar system, but also to the growing
number of extra-solar discoveries.
Willie R. Meghar