The Final IAU Resolution on the definition of "planet" ready for voting
Dr.TeKtOn
2006. 8. 29. 13:45
24. August 2006, Prague
At
the second session of the 2006 International Astronomical Union (IAU)
General Assembly, which will be held 14:00 Thursday 24 August, members
of the IAU will vote on the Resolutions presented below. There will be
separate sequential votes on Resolution 5A and Resolution 5B.
Similarly, there will be separate votes on Resolutions 6A and 6B.
Following active discussion among IAU scientists at the IAU 2006
General Assembly in Prague, draft Resolution 6b (issued 16 August 2006)
has been updated and amended.
IAU President Ron Ekers says: "IAU's
rules for proposing resolutions are based on an open democratic process
and it is a great pleasure for the IAU Executive Committee to see the
level of engagement of so many astronomers here. We want to engage as
broad a part of the IAU community as possible in the decision-making
process to give this Resolution the best chance to be passed."
Below
are the full texts of "IAU Resolution 5a for GA-XXVI", "IAU Resolution
5b for GA-XXVI" and "IAU Resolution 6a for GA-XXVI" and "IAU Resolution
6b for GA-XXVI". The voting will take place in four steps.
The
voting on these Resolutions is expected to end today (Thursday 24
August) between 15:30 and 16:00 CEST. This is a rough estimate.
According
to the revised Statutes approved at the First Session of the General
Assembly last week, scientific issues such as Resolutions are decided
by majority of those IAU members present and voting at the business
meeting. Thus the scientific resolutions, including those on the
definition of solar system bodies, will be presented and decided by
voting of the individual members. Yellow ballots will be handed out to
all IAU members at the entrance. Members will vote by raising these
ballots in the air; the number of raised ballots will be counted. The
result of the vote should be known shortly thereafter and will be
communicated in a public statement.
Notes for editors A
press conference about the Closing Ceremony of the General Assembly,
including the results of the planet-definition vote, will be held at
18:00, in Meeting Room 3.3 of the Prague Congress Center. (It will NOT
be possible for journalists to ring in to this conference: they must be
there in person.)
The panel for the press conference will be:
Ron Ekers (outgoing IAU President)
Catherine Cesarsky (incoming IAU President, Member of the Planet Definition Committee)
Jan Palous (Chair of the National Organising Committee)
Richard Binzel (Member of the Planet Definition Committee)
Karel van der Hucht (incoming Secretary General)
This press conference will conclude around 18:30 CEST.
The
IAU is the international astronomical organisation that brings together
distinguished astronomers from all nations of the world. Its mission is
to promote and safeguard the science of astronomy in all its aspects
through international cooperation. Founded in 1919, the IAU is the
world's largest professional body for astronomers. The IAU General
Assembly is held every three years and is one of the largest and most
diverse meetings on the astronomical community's calendar.
Contacts Following
the vote, some of the members of the planet definition committee will
be available for interviews (after the final vote):
Richard Binzel Member of the Planet Definition Committee Prague Conference Center, Meeting Room 3.1 Tel: +420-261-177-110 Cell: +420-776-806-297 (during the General Assembly)
Junichi Watanabe Member of the Planet Definition Committee Prague Conference Center, Meeting Room 3.3 Tel: +420-261-177-081 Cell: +420-776-806-265 (during the General Assembly)
Iwan Williams President, IAU Division III Planetary Systems Sciences Prague Conference Center, Meeting Room 244 Tel: +420-261-177-064 Cell: +420-776-175-769 (during the General Assembly)
Owen Gingerich Chair of the IAU Planet Definition Committee Tel: via the Press Room +420-261-177-075
Professor Ron Ekers IAU President Tel: via the Press Room +420-261-177-075
Catherine Cesarsky IAU President-Elect and member of the Planet Definition Committee Tel: via the Press Room +420-261-177-075
PIO contact Lars Lindberg Christensen IAU Press Officer IAU GA 2006 Press office, Meeting Room 3.2 Prague Congress Center Tel: +420-261-177-075/+420-261-222-130 Cellular: +49-173-3872-621 E-mail: lars@eso.org
RESOLUTIONS Resolution
5A is the principal definition for the IAU usage of "planet" and
related terms. Resolution 5B adds the word "classical" to the
collective name of the eight planets Mercury through Neptune.
Resolution
6A creates for IAU usage a new class of objects, for which Pluto is the
prototype. Resolution 6B introduces the name "plutonian objects" for
this class. The Merriam-Webster dictionary defines "plutonian" as: Main Entry: plu ?to ?ni ?an Pronunciation: pl?'tO-nE-&n Function: adjective Usage: often capitalized : of, relating to, or characteristic of Pluto or the lower world
After
having received inputs from many sides -- especially the geological
community -- the term "Pluton" is no longer being considered.
IAU Resolution: Definition of a Planet in the Solar System Contemporary
observations are changing our understanding of planetary systems, and
it is important that our nomenclature for objects reflect our current
understanding. This applies, in particular, to the designation
'planets'. The word 'planet' originally described 'wanderers' that were
known only as moving lights in the sky. Recent discoveries lead us to
create a new definition, which we can make using currently available
scientific information.
RESOLUTION 5A The
IAU therefore resolves that planets and other bodies in our Solar
System be defined into three distinct categories in the following way:
(1) A planet1
is a celestial body that (a) is in orbit around the Sun, (b) has
sufficient mass for its self-gravity to overcome rigid body forces so
that it assumes a hydrostatic equilibrium (nearly round) shape, and (c)
has cleared the neighbourhood around its orbit.
(2) A dwarf
planet is a celestial body that (a) is in orbit around the Sun, (b) has
sufficient mass for its self-gravity to overcome rigid body forces so
that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects3 orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. 2An IAU process will be established to assign borderline objects into either dwarf planet and other categories. 3These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
RESOLUTION 5B Insert the word "classical" before the word "planet" in Resolution 5A, Section (1), and footnote 1. Thus reading:
