[meteorite-list] 'Plutons' Push Planet Total Up To 12

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Wed Aug 16 03:05:52 2006
Message-ID: <095401c6c102$623abdb0$6a4fe146_at_ATARIENGINE>

Hi,


    Yes, Ceres is a planet again... if a vote of the whole is in favor!
I predict a cantankerous electorate on August 24th! Ceres was a
planet officially from 1804 to 1864, In 1855, the Big Four were
retained as planets but all the others were demoted to minor planets.
In the US, Ceres continued to be mentioned as a planet up into
the 1870's.

    All planets have official planet symbols, you know. We've
all seen them; they're on jewelry even. Is there a market for
a new symbol for the new planets (if they vote'em into the
club)? Well, Ceres, Vesta, Pallas, and Juno already have
symbols from back when they were planets the other time.
Good old Naval Observatory has 'em:
http://aa.usno.navy.mil/hilton/AsteroidHistory/minorplanets.html

    But "Xena" and the other qualifying crutons, er, plutons
don't. Probably have to wait until they have names...

    Ceres and the rest of the Big Four, even in 1864, were
thought to be much larger than they really are. "At the time...
the most widely disseminated values for the diameters of
the first four asteroids discovered were Ceres, 2613 km
(really 975x909); Pallas, 3380 km (really 570x525x500);
Juno, 2290 km (really 290x240x190); and Vesta (really
578x560x458), not more than 383 km." Well, they were
close on Vesta... You'll notice that only Ceres is really
ROUND enough...

    Ceres density 2.08. Pluto density 2.03. Both densities are
most easily modeled by a 50-50 mixture of ice 1.0 and rock 3.0,
or some quibbly variation thereof. However, Ceres is darker
(albedo 0.113 versus 0.50). There are signs Ceres has a transient
atmosphere like Pluto. Ceres appears to have complex organic
chemistry, so it may be the solar system's largest carbonaceous
chondrite!
http://www-ssc.igpp.ucla.edu/dawn/newsletter/html/20030822/ceres_evolution.html

    The DAWN mission will get to Vesta October 2011
and reach Ceres February 2015. Both Vesta and Ceres
will be full-surface mapped. DAWN will carry two LDR
LEON2 chip framing cameras as described below:
http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=DAWN&ex=1

    The resolution on the low-orbit passes will be a sharp
5 meters per pixel, roughly comparable to the Mars HiRISE
camera. It'll be stupendous. I really hope I live until 2015.

    Brian Marsden, in the article below:
<http://www.space.com/scienceastronomy/050802_planet_definition.html>
is quoted as saying if the Allan Stern definition of a planet
were used (everything spherical that goes 'round its star
and doesn't fusion inside), we'd have 24 planets.
    Marsden wasn't in favor of the Stern definition, and
it appears that the Stern definition is pretty much what
the IAU Committee submitted for a vote.
    But, the way they're putting it forward is that Pluto
stays, Ceres gets planet status (again), 2003UB313
is a planet and Brown gets to apply for a planet name.
Now, there's a moment in an astronomer's life!

    I think Marsden was exaggerating (he's in charge
of non-planets and the shepperd could lose some sheep)
when he said 24. Stern says 20... Let's start counting.

    Ceres is Planet 5. Jupiter, Saturn, Uranus, Neptune
all get their numbers bumped up one. Pluto, the "nineth"
planet (might be) is now Planet X (for Ten) and Charon
is Planet 11. If we add 2003UB313 ("Xena"), 2003FY9,
2003EL61, Sedna, and Quaoar we have 16 planets.
Now, can everybody spell Q U A O A R ?
Can ANYBODY say it?

    Whoops! We have to add 90482 Orcus; it's bigger
than Quaoar. That makes 17 planets. There are five
more KBO's for which a case could be made, except
that circularity might be a problem; they're smaller and
could be irregular. That would be 22 planets. Or 24.
Or 20. Schoolchildren are going hate us! 17 planets to
memorize ("Do I gotta?!") AND learn how to spell
QUAOAR?

    Somebody is sure to get offensive about 2003EL61
just because it isn't round. I think we need an exception
for dynamic distortion. Yeah, true 2003EL61 is about
1960 x 1520 x 1000 km. Not very round. OK, it had this
really rough childhood, see... But its density is almost
as great as the Earth's Moon! This is no iceball! It's
solid rock. It rotates in 4 hours; it's dynamically distorted,
So is Jupiter and all other rotating bodies. Even I have a mild
equatorial bulge and I'm not spinning at all.


Sterling K. Webb
---------------------------------------------------------------------
----- Original Message -----
From: "Darren Garrison" <cynapse_at_charter.net>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, August 15, 2006 11:17 PM
Subject: Re: [meteorite-list] 'Plutons' Push Planet Total Up To 12


On Tue, 15 Aug 2006 23:04:18 -0500, you wrote:

> Spoze he meant CHIRON?

Naming a drug company as a planet would be even more of a problem. What
would
be next, planet Eily Lilly?

On a more serious note, the article mentions Ceres. I'm not clear on this,
were
they saying that Ceres would be given planet status? Surely it wouldn't be
lumped in as a cruton... I mean Pluton?
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Received on Wed 16 Aug 2006 03:05:40 AM PDT