by Ludwig Scheibe (TU Berlin), April 2025
The International Astronomical Union (IAU) is a non-government organization dedicated to promoting astronomy. It is headquartered in Paris, France and maintains several offices in other countries.
Members are mostly astronomers of various levels, from doctoral students to senior scientists (“individual members”). There are also a number of national astronomical societies who are so-called “national members” in the IAU, among them the Rat Deutscher Sternwarten (Council of German Observatories), which is a part of the German Astronomical Society. They are organised in a number of divisions, commissions and working groups, each dedicated to a specific subject area.
A big part of the IAU’s work is the facilitation of scientific conferences. Each year, international symposia are sponsored and organised by the IAU. There is also the General Assembly every three years, with the host location going to a different country every time.
Furthermore, the IAU standardises astronomical constants and nomenclature. For example, in 2006 they adopted a definition of what a Solar System Planet is, and in 2018 they adopted a working definition for the word Exoplanet. Learn more about what makes a planet here. They also are the internationally accepted body to assign names to “extraterrestrial features” – which means they chose names for astronomical bodies like comets, stars and planets, and for surface features on them, like craters or mountains. In that function, the IAU periodically runs the NameExoworlds project, where it solicits suggestions for the name of some of the more notable exoplanets.
The IAU is also very active in astronomical outreach, education and science communication, with several working groups and offices dedicated to that subject, for example the Office for Astronomy and Education in cooperation with the Max Planck Institute for Astronomy, and the Office for Astronomy Outreach in cooperation with the National Astronomical Observatory of Japan.
Learn more about the IAU and its various activities on their official website.
The results of the IAU conferences are regularly published in the Proceedings of the International Astronomical Union.