IAU 2006 General Assembly: Result of the IAU Resolution votes(Forwarded)

International Astronomical Union
Paris, France

24 August 2006

IAU 2006 General Assembly: Result of the IAU Resolution votes

Prague, Czech Republic -- The first half of the Closing Ceremony of the
2006 International Astronomical Union (IAU) General Assembly has just
concluded. The results of the Resolution votes are outlined here.

It is official: The 26th General Assembly for the International
Astronomical Union was an astounding success! More than 2500 astronomers
participated in six Symposia, 17 Joint Discussions, seven Special Sessions
and four Special Sessions. New science results were vigorously discussed,
new international collaborations were initiated, plans for future
facilities put forward and much more.

In addition to all the exciting astronomy discussed at the General
Assembly, six IAU Resolutions were also passed at the Closing Ceremony of
the General Assembly:

1. Resolution 1 for GA-XXVI: "Precession Theory and Definition of the
Ecliptic"
2. Resolution 2 for GA-XXVI: "Supplement to the IAU 2000 Resolutions on
reference systems"
3. Resolution 3 for GA-XXVI: "Re-definition of Barycentric Dynamical Time,
TDB"
4. Resolution 4 for GA-XXVI: "Endorsement of the Washington Charter for
Communicating Astronomy with the Public"
5. Resolution 5A: "Definition of 'planet' "
6. Resolution 6A: "Definition of Pluto-class objects"

The IAU members gathered at the 2006 General Assembly agreed that a
"planet" is defined as 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.

This means that the Solar System consists of eight "planets" Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A new distinct
class of objects called "dwarf planets" was also decided. It was agreed
that "planets" and "dwarf planets" are two distinct classes of objects.
The first members of the "dwarf planet" category are Ceres, Pluto and 2003
UB313 (temporary name). More "dwarf planets" are expected to be announced
by the IAU in the coming months and years. Currently a dozen candidate
"dwarf planets" are listed on IAU's "dwarf planet" watchlist, which keeps
changing as new objects are found and the physics of the existing
candidates becomes better known.

The "dwarf planet" Pluto is recognised as an important proto-type of a new
class of trans-Neptunian objects. The IAU will set up a process to name
these objects.

Below are the planet definition Resolutions that were passed.

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
[1600 UTC], 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 [1630 UTC].

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


Junichi Watanabe
Member of the Planet Definition Committee
Prague Conference Center, Meeting Room 3.3
Tel: +420-261-177-081


Iwan Williams
President, IAU Division III Planetary Systems Sciences
Prague Conference Center, Meeting Room 244
Tel: +420-261-177-064


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


Links

* Programme for the Closing Ceremony
http://www.astronomy2006.com/second-...g-ceremony.php
* Live public webcast of the Closing Ceremony
http://astronomy2006.com/tv/
* Live press webcast of the Closing Ceremony (press only, please do not
distribute)
http://www.astronomy2006.com/tv-press
* The IAU Web page
http://www.iau.org
* IAU News during the 2006 General Assembly
http://www.iau2006.org
* IAU General Assembly
http://www.astronomy2006.com
* Free registration for the media
http://www.astronomy2006.com/media-accreditation.php

RESOLUTIONS

Resolution 5A is the principal definition for the IAU usage of "planet"
and related terms.

Resolution 6A creates for IAU usage a new class of objects, for which
Pluto is the prototype. The IAU will set up a process to name these
objects.

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 "planet" [1] 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) shape
[2] , (c) has not cleared the neighbourhood around its orbit, and (d) is
not a satellite.

(3) All other objects [3] except satellites orbiting the Sun shall be
referred to collectively as "Small Solar-System Bodies".

[1] The eight planets a Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune.
[2] An IAU process will be established to assign borderline objects into
either dwarf planet and other categories.
[3] These currently include most of the Solar System asteroids, most
Trans-Neptunian Objects (TNOs), comets, and other small bodies.

IAU Resolution: Pluto

RESOLUTION 6A

The IAU further resolves:

Pluto is a "dwarf planet" by the above definition and is recognized as the
prototype of a new category of trans-Neptunian objects.