International Astronomical Union

International Astronomical Union (IAU)

Union astronomique internationale (UAI)
National members from 85 countries as of May 2023   Member states   States with interim status   Observer states   Suspended states
Abbreviation	IAU/UAI
Formation	28 July 1919; 105 years ago (28 July 1919)
Founded at	Brussels, Belgium
Type	INGO
Headquarters	Paris, France
Region served	Worldwide
Membership	85 national members[1] 12,734 individual members[2]
President	Debra Meloy Elmegreen
General Secretary	Piero Benvenuti (interim)[3]
Website	IAU.org

The International Astronomical Union (IAU; French: Union astronomique internationale, UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation. It was founded on 28 July 1919 in Brussels, Belgium 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 May 2024,^[update] the Union had 85 national members and 12,734 individual members, spanning 90 countries and territories.^[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, which is composed of international scholarly and scientific institutions and national academies of sciences.