[extropy-chat] Our Solar System Planets

[Amara Graps]

The planets in our Solar System are now 12:

Mercury
Venus
Earth
Mars
Ceres
Jupiter
Saturn
Uranus
Neptune
Pluto
Charon
2003 UB313


To make the most sense, read the docs in order.
  1. Press Release    2. Resolution text    3. Questions & Answers


Press release:
http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html

Resolution text:
http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_resolution.html

Question and Answers:
http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_Q_A.html


Forwarded in an email from Mark Sykes, (PSI), who forwarded
it from Richard Binzel at the IAU meeting in Prague:


BRIEF SUMMARY (TWO PARTS)

A.  Planet = Hydrostatic Equilibrium Shape.
     Therefore:
      -Pluto status as planet remains unchanged.
      -There are currently 12 planets, and counting.
      -Ceres now a planet.
      -Charon now a planet (not a satellite; barycenter is in free space)
-2003 UB313 now a planet; will be named after IAU Meeting.

B.  New IAU Category of planets created: "Plutons"
      -Pluto is the prototype.
      -Many new planets to be added, these will be the largest TNOs
       that satisfy the "planet" definition.  (IAU may create a
       separate "pluton catalog".  This is a separate discussion.)
      -Currently three objects recognized as "plutons":
          Pluto, Charon, UB313.
      -New discoveries of large objects (and currently known large TNOs)
       to be evaluated for "planet" status on a case by case basis.
"Planets" among the TNOs are also known as "Plutons".

NOTE:  "Pluton" is an official IAU word.
        Terrestrial planet, classical planet, dwarf planet, etc.
        are all descriptive words, not IAU terms.  We want to work
        hard to NOT have "classical planet", "dwarf planet" be mis-
        interpreted as official IAU categories.  They are not.
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-- 

Amara Graps, PhD      www.amara.com
Istituto di Fisica dello Spazio Interplanetario (IFSI), Roma, ITALIA
Associate Research Scientist, Planetary Science Institute (PSI), Tucson