The IAU is a member of the International Council for Science (ICSU). Its main objective is to promote and safeguard the science of astronomy in all its aspects through international cooperation. The IAU maintains friendly relations with organizations that include amateur astronomers in their membership. The IAU has its head office on the second floor of the Institut d’Astrophysique de Paris. The IAU is also responsible for the system of astronomical telegrams which are produced and distributed on its behalf by the Central Bureau for Astronomical Telegrams. The Minor Planet Center (MPC), a clearinghouse for all non-planetary or non-moon bodies in the solar system, also operates under the IAU.
The IAU was founded in 1919, as a merger of various international projects including the Carte du Ciel, the Solar Union and the International Time Bureau (Bureau International de l’Heure). The first appointed President was Benjamin Baillaud. Pieter Johannes van Rhijn served as president from 1932 to 1958. In the IAU Information Bulletin No. 100, twelve of the fourteen past General Secretaries since 1964, each one in office for the three years between General Assemblies, recall the IAU history with its difficulties, e.g. with Soviet bloc officials, with the Greek military junta, and the reasons behind the unpopular decision to hold an additional Extraordinary General Assembly in Poland on the occasion of Nicolaus Copernicus‘ 500th birthday in February 1973, shortly after the regular GA in Australia.
The IAU has 10,871 individual members, all of whom are professional astronomers and most of whom hold PhDs. There are also 73 nationalmembers who represent countries affiliated with the IAU. 86% of individual members are male, while 14% are female, among them the union’s former president, astronomer Catherine J. Cesarsky.
The sovereign body of the IAU is its General Assembly, which comprises all members. The Assembly determines IAU policy, approves the Statutes and By-Laws of the Union (and amendments proposed thereto) and elects various committees.
The right to vote on matters brought before the Assembly varies according to the type of business under discussion. The Statutes consider such business to be divided into two categories:
- issues of a “primarily scientific nature” (as determined by the Executive Committee), upon which voting is restricted to individual members, and
- all other matters (such as Statute revision and procedural questions), upon which voting is restricted to the representatives of national members.
On budget matters (which fall into the second category), votes are weighted according to the relative subscription levels of the national members. A second category vote requires a turnout of at least two-thirds of national members in order to be valid. An absolute majority is sufficient for approval in any vote, except for Statute revision which requires a two-thirds majority. An equality of votes is resolved by the vote of the President of the Union.
Since 1922, the IAU General Assembly meets every three years, with the exception of the period between 1938 to 1948, due to World War II. After a Polish request in 1967, and by a controversial decision of the then President of the IAU, an Extraordinary IAU General Assembly was held in February 1973 in Warsaw, Poland, to commemorate the 500th anniversary of the birth of Nicolaus Copernicus, soon after the regular 1973 GA had been held in Australia.
|Ist IAU General Assembly (1st)||1922||Rome, Italy|
|IInd IAU General Assembly (2nd)||1925||Cambridge, England, United Kingdom|
|IIIrd IAU General Assembly (3rd)||1928||Leiden, Netherlands|
|IVth IAU General Assembly (4th)||1932||Cambridge, Massachusetts, United States|
|Vth IAU General Assembly (5th)||1935||Paris, France|
|VIth IAU General Assembly (6th)||1938||Stockholm, Sweden|
|VIIth IAU General Assembly (7th)||1948||Zürich, Switzerland|
|VIIIth IAU General Assembly (8th)||1952||Rome, Italy|
|IXth IAU General Assembly (9th)||1955||Dublin, Ireland|
|Xth IAU General Assembly (10th)||1958||Moscow, Soviet Union|
|XIth IAU General Assembly (11th)||1961||Berkeley, California, United States|
|XIIth IAU General Assembly (12th)||1964||Hamburg, West Germany|
|XIIIth IAU General Assembly (13th)||1967||Prague, Czechoslovakia|
|XIVth IAU General Assembly (14th)||1970||Brighton, England, United Kingdom|
|XVth IAU General Assembly (15th)||1973||Sydney, New South Wales, Australia|
|XVIth IAU General Assembly (16th)||1976||Grenoble, France|
|XVIIth IAU General Assembly (17th)||1979||Montreal, Quebec, Canada|
|XVIIIth IAU General Assembly (18th)||1982||Patras, Greece|
|XIXth IAU General Assembly (19th)||1985||New Delhi, India|
|XXth IAU General Assembly (20th)||1988||Baltimore, Maryland, United States|
|XXIst IAU General Assembly (21st)||1991||Buenos Aires, Argentina|
|XXIInd IAU General Assembly (22nd)||1994||The Hague, Netherlands|
|XXIIIrd IAU General Assembly (23rd)||1997||Kyoto, Japan|
|XXIVth IAU General Assembly (24th)||2000||Manchester, England, United Kingdom|
|XXVth IAU General Assembly (25th)||2003||Sydney, New South Wales, Australia|
|XXVIth IAU General Assembly (26th)||2006||Prague, Czech Republic|
|XXVIIth IAU General Assembly (27th)||2009||Rio de Janeiro, Brazil|
|XXVIIIth IAU General Assembly (28th)||2012||Beijing, China|
|XXIXth IAU General Assembly (29th)||2015||Honolulu, Hawaii, United States|
|XXXth IAU General Assembly (30th)||2018||Vienna, Austria|
|XXXIst IAU General Assembly (31st)||2021||Busan, South Korea|
The XXVIth General Assembly and the definition of a planet
The XXVIth General Assembly of the International Astronomical Union was held from 14 to 25 August 2006 in Prague, Czech Republic. On 15 August the Assembly decided to restore to individual members the right to vote on scientific matters, which had been removed from them at the XXVth Assembly in 2003. Among the business before the Assembly was a proposal to adopt a formal definition of planet. During the General Assembly the text of the definition evolved from the initial proposal that would have created 12 known planets in the solar system (adding the asteroid that was briefly considered a planet in 1801, Ceres, Pluto‘s present moon Charon, Eris, and would retain Pluto as a planet) to the final definition of a planet resolution that was passed on 24 August by the Assembly, which classified Ceres, Eris and Pluto as dwarf planets, and reduced the number of planets in the solar system to 8. The voting procedure followed IAU’s Statutes and Working Rules. The General Assembly lasted 12 days and had 2412 participants, most of them for only part of the duration of the Assembly. 424 of the 9785 individual IAU members attended the Closing Ceremony on 24 August 2006. Following the Closing Ceremony, parts of the scientific community did not agree with this ruling, especially the specific wording of the resolution. In the ensuing public debate, a number of laypersons expressed (at times strong) disagreement with the vote. Another, less vocal, fraction of the scientific community backs the resolution, including the discoverer of the dwarf planet Eris, Mike Brown.
A final decision was made, announced 11 June 2008, for acceptance of the term Plutoid and its official IAU definition:
Plutoids are celestial bodies in orbit around the Sun at a semimajor axis greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. Satellites of plutoids are not plutoids themselves.
The Commission 46: Education in astronomy
Commission 46 is a Committee of the Executive Committee of the IAU. As a prestigious international scientific union, the IAU plays a special role in the discussion of astronomy development with governments and scientific academies and in interceding about such matters at the highest levels. The IAU is affiliated with the International Council of Scientific Unions (ICSU), a non-governmental organization representing a global membership that includes both national scientific bodies and international scientific unions. When appropriate, the President and officers of the IAU are proactive in persuading the authorities of the importance of astronomy for development and education and in encouraging countries to become members of the IAU. A strategic plan for the period 2010-2020 has been published.
The Commission seeks to further the development and improvement of astronomical education at all levels throughout the world, through various projects initiated, maintained, and to be developed by the Commission and by disseminating information concerning astronomy education at all levels. Part of Commission 46, the Teaching Astronomy for Development (TAD) program is intended to help enhance astronomy education significantly in countries where there is currently very little on offer. TAD operates on the basis of a proposal from a professional astronomy organization or a contract between the IAU and an academic institution, usually a university.
The IAU has launched in 2009 the Galileo Teacher Training Program (GTTP), a Cornerstone project of the International Year of Astronomy 2009, among which Hands-On Universe is a major partner. Hands-On Universe is now officially included in the Astronomy for the Developing World Strategic Plan 2010-20 of IAU, under Section 3.4.2 Astronomy for Children and Schools. During the next decade the IAU will concentrate more resources on education activities for children and schools designed to advance sustainable global development.
The GTTP is concerned with the effective use and transfer of astronomy education tools and resources into classroom science curricula. By training a worldwide network of “Galileo Ambassadors” who will train new “Galileo Teachers” the effect of the program will be multiplied. The GTTP is closely affiliated with the Global Hands-on Universe Program.
Outreach to teachers will involve the provision of training courses, development and translation of materials and harnessing global technological resources in the service of primary and secondary education. A specific goal will be to provide expertise for at least one teacher training course in each region every year, to be organized together with the regional coordinators.
Related programs (leader name): Hands-On Universe (Dr Roger Ferlet), and Universe Awareness (Dr Carolina Ödman).
Information resource: IAU
Fragmentation of data in hundreds of catalogs worldwide, has led to the need to create international catalog of heavenly bodies for the comprehensive development of information on astronomical bodies for centralized collection, storage and tracking of changes.
ICHB has become a controlling entity that registers names to astronomical bodies. For this purpose ICHB has developed a Unified Heavenly Bodies Catalog synchronising all major data from other registrators.
Information resource: ICHB
A special project with a limited period of validity, which provides access to the free naming of exoplanets for the general public, among valid members of the IAU.
The ExoWorlds list of exoplanets and their host stars being available for public naming at the initiative of the IAU is a list compiled from several exoplanet databases, included in ICHB. The ICHB supports this initiative to attract the general public to the naming of space bodies.
This list includes well-studied exoplanets discovered over twenty years, up to 31 December 2008. A period of at least five years since the discovery has been considered as a simple and satisfactory criterion to include exoplanets which can be considered as confirmed. All the discoveries were made using various methods, including radial velocities, transits, microlensing and direct imagery.
For these exoplanets, the scientific nomenclature follows the nomenclature rules widely adopted by the scientific community, which are drawn from the rules for naming binary stars. For each planet, the name of the host star (around which planets are orbiting) is followed by a lower-case letter: b for the first discovered exoplanet, c for the second, etc. (The letters are capitalized in the case of binaries: the “primary” star name is followed by “A”, and its companion stars are labelled by the same name followed by “B”, “C”, etc.).
In the ExoWorlds list, five stars already have common names: Fomalhaut (alpha Piscis Austrini) is one of the four “royal stars” of ancient Persia, with Aldebaran, Antares, and Regulus; Pollux (beta Geminorum) is the twin brother of Castor, son of Zeus (Jupiter) and Leda, from the ancient Greek and Roman mythologies — the constellation Gemini is named after them (Gemini means twins in latin). Three other stars also have common names: gamma Cephei (Errai, Arabic for shepherd), epsilon Tauri (Ain, Arabic for the bull’s eye) and iota Draconis (Edasich, Arabic also). These stars have common names as well in other cultures.
Consequently these five stars cannot be considered for public naming.
Project site: NameExoWorlds (At this moment the project is over. We’ll let you know if it opens again.)