International Astronomical Union

Last updated

International Astronomical Union (IAU)
Union astronomique internationale (UAI)
Formation28 July 1919;104 years ago (28 July 1919)
Founded at Brussels, Belgium
HeadquartersParis, France
85 national members [1]
12,131 individual members [2]
Debra Meloy Elmegreen
Piero Benvenuti [3]
Website OOjs UI icon edit-ltr-progressive.svg

The International Astronomical Union (IAU; French : Union astronomique internationale, UAI) is a non-governmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation. It was founded in 1919 and is based in Paris, France.


The IAU is composed of individual members, who include both professional astronomers and junior scientists, and national members, such as professional associations, national societies, or academic institutions. Individual members are organised into divisions, committees, and working groups centered on particular subdisciplines, subjects, or initiatives. As of 2018, the Union had over 13,700 individual members, spanning 90 countries, and 82 national members. [4]

Among the key activities of the IAU is serving as a forum for scientific conferences. It sponsors nine annual symposia and holds a triannual General Assembly that sets policy and includes various scientific meetings. The Union is best known for being the leading authority in assigning official names and designations to astronomical objects, and for setting uniform definitions for astronomical principles. It also coordinates with national and international partners, such as UNESCO, to fulfill its mission.

The IAU is a member of the International Science Council (ISC), which is composed of international scholarly and scientific institutions and national academies of sciences.


The International Astronomical Union is an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy. [5] Among other activities, it acts as the recognized authority for assigning designations and names to celestial bodies (stars, planets, asteroids, etc.) and any surface features on them. [6]

The IAU is a member of the International Science Council (ISC). 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 in the 14th arrondissement of Paris. [7]

This organisation has many working groups. For example, the Working Group for Planetary System Nomenclature (WGPSN), which maintains the astronomical naming conventions and planetary nomenclature for planetary bodies, and the Working Group on Star Names (WGSN), which catalogues and standardizes proper names for stars. 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 also operates under the IAU, and is a "clearinghouse" for all non-planetary or non-moon bodies in the Solar System. [8]


The IAU was founded on 28 July 1919, at the Constitutive Assembly of the International Research Council (now the International Science Council) held in Brussels, Belgium. [9] [10] Two subsidiaries of the IAU were also created at this assembly: the International Time Commission seated at the International Time Bureau in Paris, France, and the International Central Bureau of Astronomical Telegrams initially seated in Copenhagen, Denmark. [9]

The seven initial member states were Belgium, Canada, France, Great Britain, Greece, Japan, and the United States, soon to be followed by Italy and Mexico. [9] The first executive committee consisted of Benjamin Baillaud (President, France), Alfred Fowler (General Secretary, UK), and four vice presidents: William Campbell (US), Frank Dyson (UK), Georges Lecointe (Belgium), and Annibale Riccò (Italy). [9] Thirty-two Commissions (referred to initially as Standing Committees) were appointed at the Brussels meeting and focused on topics ranging from relativity to minor planets. The reports of these 32 Commissions formed the main substance of the first General Assembly, which took place in Rome, Italy, 2–10 May 1922.

By the end of the first General Assembly, ten additional nations (Australia, Brazil, Czechoslovakia, Denmark, the Netherlands, Norway, Poland, Romania, South Africa, and Spain) had joined the Union, bringing the total membership to 19 countries. Although the Union was officially formed eight months after the end of World War I, international collaboration in astronomy had been strong in the pre-war era (e.g., the Astronomische Gesellschaft Katalog projects since 1868, the Astrographic Catalogue since 1887, and the International Union for Solar research since 1904). [9]

The first 50 years of the Union's history are well documented. [9] [10] Subsequent history is recorded in the form of reminiscences of past IAU Presidents and General Secretaries. Twelve of the fourteen past General Secretaries in the period 1964–2006 contributed their recollections of the Union's history in IAU Information Bulletin No. 100. [11] Six past IAU Presidents in the period 1976–2003 also contributed their recollections in IAU Information Bulletin No. 104. [12]

In 2015 and 2019, the Union held the NameExoWorlds contests. [13] [14]

Starting in 2024, the Union, in partnership with the United Nations, is poised to play a critical role in developing the legislation and framework for lunar industrialization. [15]


The IAU includes member organizations from 82 countries (designated as national members). IAU National Members.svg
The IAU includes member organizations from 82 countries (designated as national members).

As of 1 August 2019, the IAU has a total of 13,701 individual members, who are professional astronomers from 102 countries worldwide; 81.7% of individual members are male, while 18.3% are female. [2]

Membership also includes 82 national members, professional astronomical communities representing their country's affiliation with the IAU. National members include the Australian Academy of Science, the Chinese Astronomical Society, the French Academy of Sciences, the Indian National Science Academy, the National Academies (United States), the National Research Foundation of South Africa, the National Scientific and Technical Research Council (Argentina), the Council of German Observatories, the Royal Astronomical Society (United Kingdom), the Royal Astronomical Society of New Zealand, the Royal Swedish Academy of Sciences, the Russian Academy of Sciences, and the Science Council of Japan, among many others. [1]

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:

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 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.

List of national members




North America


South America

Terminated national members

General Assemblies

Since 1922, the IAU General Assembly meets every three years, except for the period between 1938 and 1948, due to World War II. After a Polish request in 1967, and by a controversial decision [16] of the then President of the IAU, an Extraordinary IAU General Assembly was held in September 1973 in Warsaw, Poland, [17] to commemorate the 500th anniversary of the birth of Nicolaus Copernicus, soon after the regular 1973 GA had been held in Sydney.

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)1935Paris, 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)1958Moscow, 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)1973Sydney, 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)1985New 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)2003Sydney, 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)2012Beijing, China
XXIXth IAU General Assembly (29th)2015 Honolulu, Hawaii, United States
XXXth IAU General Assembly (30th)2018 Vienna, Austria
XXXIst IAU General Assembly (31st)2022 [18] Busan, South Korea
XXXIInd IAU General Assembly (32nd)2024 Cape Town, South Africa [19]

List of the presidents of the IAU

Sources. [20] [21]


Commission 46: Education in astronomy

Commission 46 is a Committee of the Executive Committee of the IAU, playing a special role in the discussion of astronomy development with governments and scientific academies. 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. They often encourage countries to become members of the IAU. The Commission further seeks to development, information or improvement of astronomical education. Part of Commission 46, is Teaching Astronomy for Development (TAD) program in countries where there is currently very little astronomical education. Another program is named the Galileo Teacher Training Program (GTTP), is a project of the International Year of Astronomy 2009, among which Hands-On Universe that will concentrate more resources on education activities for children and schools designed to advance sustainable global development. GTTP is also concerned with the effective use and transfer of astronomy education tools and resources into classroom science curricula. A strategic plan for the period 2010–2020 has been published. [23]


Cover picture of CAP Journal issue 19, March 2016 Cover picture of CAPjournal issue 19 (ann16014a).jpg
Cover picture of CAP Journal issue 19, March 2016

In 2004 the IAU contracted with the Cambridge University Press to publish the Proceedings of the International Astronomical Union. [25]

In 2007, the Communicating Astronomy with the Public Journal Working Group prepared a study assessing the feasibility of the Communicating Astronomy with the Public Journal (CAP Journal). [26]

See also

Related Research Articles

<span class="mw-page-title-main">Astronomer</span> Scientist in the field of astronomy

An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either observational or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, solar astronomy, the origin or evolution of stars, or the formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole.

<span class="mw-page-title-main">Astronomical object</span> Large natural physical entity in space

An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms object and body are often used interchangeably. However, an astronomical body or celestial body is a single, tightly bound, contiguous entity, while an astronomical or celestial object is a complex, less cohesively bound structure, which may consist of multiple bodies or even other objects with substructures.

In ancient times, only the Sun and Moon, a few stars, and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered every year. Astronomers need to be able to assign systematic designations to unambiguously identify all of these objects, and at the same time give names to the most interesting objects, and where relevant, features of those objects.

Richard Martin West is a Danish astronomer and discoverer of astronomical objects with a long career at the European Southern Observatory (ESO) and at the International Astronomical Union (IAU).

<span class="mw-page-title-main">Bart Bok</span> American astronomer and lecturer (1906–1983)

Bartholomeus Jan "Bart" Bok was a Dutch-American astronomer, teacher, and lecturer. He is best known for his work on the structure and evolution of the Milky Way galaxy, and for the discovery of Bok globules, which are small, densely dark clouds of interstellar gas and dust that can be seen silhouetted against brighter backgrounds. Bok suggested that these globules may be in the process of contracting, before forming into stars.

<span class="mw-page-title-main">Elizabeth Roemer</span> American astronomer

Elizabeth "Pat" Roemer was an American astronomer and educator who specialized in astronomy with a particular focus on comets and minor planets. She was well-known for the recovery of lost comets, as well as for her discovery of two asteroids, the co-discovery of Jupiter's moon Themisto, and for the asteroid 1657 Roemera that was named in her honor.

PSR B1257+12, previously designated PSR 1257+12, alternatively designated PSR J1300+1240, is a millisecond pulsar located 2,300 light-years from the Sun in the constellation of Virgo, rotating at about 161 times per second. It is also named Lich, after a powerful, fictional undead creature of the same name.

The definition of the term planet has changed several times since the word was coined by the ancient Greeks. Greek astronomers employed the term ἀστέρες πλανῆται, 'wandering stars', for star-like objects which apparently moved over the sky. Over the millennia, the term has included a variety of different celestial bodies, from the Sun and the Moon to satellites and asteroids.

<span class="mw-page-title-main">International Year of Astronomy</span> 2009 UN theme year

The International Year of Astronomy (IYA2009) was a year-long celebration of astronomy that took place in 2009 to coincide with the 400th anniversary of the first recorded astronomical observations with a telescope by Galileo Galilei and the publication of Johannes Kepler's Astronomia nova in the 17th century. The Year was declared by the 62nd General Assembly of the United Nations. A global scheme, laid out by the International Astronomical Union (IAU), was also endorsed by UNESCO, the UN body responsible for educational, scientific, and cultural matters.

<span class="mw-page-title-main">Dwarf planet</span> Small planetary-mass object

A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System. The prototypical dwarf planet is Pluto, which for decades was regarded as a planet before the "dwarf" concept was adopted in 2006.

IAU definition of <i>planet</i> 2006 International Astronomical Union definition

The International Astronomical Union (IAU) defined in August 2006 that, in the Solar System, a planet is a celestial body that:

  1. is in orbit around the Sun,
  2. has sufficient mass to assume hydrostatic equilibrium, and
  3. has "cleared the neighbourhood" around its orbit.

Elena Vladimirovna Pitjeva is a Russian astronomer working at the Institute of Applied Astronomy, Russian Academy of Sciences, St. Petersburg. She has published over 100 articles, as listed in Google Scholar and the Astrophysics Data System in the field of solar system dynamics and celestial mechanics.

Priscilla Fairfield Bok was an American astronomer and the wife of Dutch-born astronomer Bart Bok, Director of Mount Stromlo Observatory in Australia and later of Steward Observatory in Arizona, US. Their harmonious marriage accompanied the four decades of their close scientific collaboration, in which "it is difficult and pointless to separate his achievements from hers". They co-authored a number of academic papers on star clusters, stellar magnitudes, and the structure of the Milky Way galaxy. The Boks displayed great mutual enthusiasm for explaining astronomy to the public: described as "salesmen of the Milky Way" by The Boston Globe, their general interest book The Milky Way went through five editions and was said to be "one of the most successful astronomical texts ever written".

<span class="mw-page-title-main">Andrea Milani (mathematician)</span> Italian mathematician and astronomer

Andrea Milani Comparetti was an Italian mathematician and astronomer, based at the University of Pisa.

<span class="mw-page-title-main">S. M. Razaullah Ansari</span> Indian Scientist

Shaikh Mohammad Razaullah Ansari was an Indian historian of science, physicist, astronomer and writer.

<span class="mw-page-title-main">Dmitry V. Bisikalo</span>

Dmitry Valerevich Bisikalo is a Russian astrophysicist and an expert in the interaction of binary stars. He is a member of the Russian Academy of Sciences, the IAU, Acting Chief of the Scientific Secretary of the Russian Academy of Sciences and Chief Researcher of the Institute of Astronomy of the Russian Academy of Sciences (RAS).

The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education, Outreach and Heritage.

Anita L. Cochran is an American astronomer, planetary scientist, and senior research scientist at the University of Texas at Austin. She is also the assistant director for research support at the McDonald Observatory. She focuses on the study of primitive bodies in the solar system and the composition of comets.

<span class="mw-page-title-main">Gloria Dubner</span> Argentina astrophysicist

Gloria Dubner is an Argentinian astrophysicist and Director of the Instituto de Astronomía y Física del Espacio in Buenos Aires and a Senior Researcher at the National Scientific and Technical Research Council. She is known for her research on supernovas.

<span class="mw-page-title-main">Teresa Lago</span> Portuguese astronomer

Maria Teresa Vaz Torrão Lago is a Portuguese astronomer who founded the Centre for Astrophysics of the University of Porto and created the first astronomy degree program in Portugal. Lago is currently the General Secretary of the International Astronomical Union. Her research focuses on the evolution of young stars and she is active in the promotion of astronomy and scientific culture to the public.


  1. 1 2 "National Members".
  2. 1 2 "Geographical and Gender Distribution of Individual Members".
  3. "International Astronomical Union | IAU". Retrieved 24 October 2023.
  4. "International Astronomical Union | IAU". Retrieved 2 July 2021.
  5. "About the IAU". International Astronomical Union. Retrieved 11 October 2016.
  6. Overbye, Dennis (4 August 2014). "You Won't Meet the Beatles in Space – Plan to Liven Official Naming of Stars and Planets Hits Clunky Notes". The New York Times . Retrieved 11 October 2016.
  7. "IAU Secretariat." International Astronomical Union. Retrieved 26 May 2011. "Address: IAU – UAI Secretariat 98-bis Blvd Arago F–75014 PARIS FRANCE" and "The IAU Secretariat is located in the Institut d'Astrophysique de Paris, 2nd floor, offices n°270, 271 and 283."
  8. "Centres – Minor Planet Center". International Astronomical Union. Retrieved 20 April 2016.
  9. 1 2 3 4 5 6 Blaauw, Adriaan (1994). History of the IAU : the birth and first half-century of the International Astronomical Union. Dordrecht: Kluwer Academic Publishers. ISBN   0-7923-2979-1.
  10. 1 2 Adams, Walter S. (February 1949). "The History of the International Astronomical Union". Publications of the Astronomical Society of the Pacific. 61 (358): 5. Bibcode:1949PASP...61....5A. doi: 10.1086/126108 .
  11. "IAU Information Bulletin No. 100, July 2007" (PDF).
  12. "IAU Information Bulletin No. 104, June 2009" (PDF).
  13. Overbye, Dennis (2 December 2016). "Twinkle, Twinkle Little [Insert Name Here]". The New York Times. ISSN   0362-4331 . Retrieved 6 June 2022.
  14. "IAU100 Name ExoWorlds". IAU100:Under One Sky. Retrieved 6 June 2022.
  15. McKie, Robin (6 January 2024). "Moon's resources could be 'destroyed by thoughtless exploitation', NASA warned". The Observer.
  16. Gingerich, Owen (1999). "The Copernican Quinquecentennial and Its Predecessors: Historical Insights and National Agendas". Osiris. 14: 50–51. Bibcode:1999Osir...14...37G. doi:10.1086/649299. JSTOR   301960. S2CID   144982060.
  17. "Extraordinary General Assembly".
  18. "International Astronomical Union | IAU".
  19. "Homepage - IAU General Assembly 2024 - Cape Town". 31 August 2023. Retrieved 24 October 2023.
  20. "Past Executive Committee". International Astronomical Union. Retrieved 18 September 2018.
  21. Колчинский И. Г., Корсунь А. А., Родригес М. Г. (1977). Астрономы. Биографический справочник (in Russian). Киев: Наукова Думка.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: multiple names: authors list (link)
  22. "International Astronomical Union". Retrieved 14 January 2022.
  23. "Astronomy for the Developing World, Building from the IYA 2009, Strategic Plan 2010–20".
  24. "CAPjournal Rosetta Special Out Now" . Retrieved 28 March 2016.
  25. "Proceedings of the International Astronomical Union". Cambridge Journals Online. Cambridge University Press . Retrieved 1 September 2015.
  26. Russo, P.; Christensen, L. L.; Iau Commission 55 Capjournal Working Group (1 June 2008). "The Communicating Astronomy with the Public journal: A study from the IAU DIVISION XII Commission 55 CAPjournal Working Group". Communicating Astronomy with the Public: 190. Bibcode:2008ca07.conf..190R.{{cite journal}}: CS1 maint: numeric names: authors list (link)