Naming of exoplanets 

The IAU fully supports the involvement of the general public in the naming of astronomical objects, whether directly or through an independent organised vote, in the naming of planetary satellites, newly discovered exoplanets, and their host stars. This follows a well-established tradition for naming Solar System objects.

The IAU does not consider itself as having a monopoly on the naming of celestial objects — anyone can in theory adopt names the way they choose. However, given the publicity and emotional investment associated with these discoveries, worldwide recognition is important and the IAU offers its unique experience for the benefit of a successful public naming process (which must remain distinct, as in the past, from the scientific designation issues)

The process for naming exoplanets is organised by the IAU Executive Committee Working Group Public Naming of Planets and Planetary Satellites.

Scientific designations

The scientific nomenclature for the designations of exoplanets is 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.).

Public naming campaigns

In order to assist in the selection process while avoiding mistakes due to incomplete information, the IAU asks organizations planning to issue a public naming campaign to do so in association with the IAU, and inform its General Secretary of their intentions and proposals. The IAU is ready to assist in resolving problems and providing relevant information. More precisely, the IAU will welcome proposals from organizations, provided the following rules are followed:

  1. Prior to any public naming initiative, often a vote (hereafter "the process”), the IAU should be contacted from the start by a Letter of Intent sent to the IAU General Secretary by an organization. Scientists or science communicators may be involved in the process;

  2. The organization should list its legal or official representatives and its goals, and explain the reasons for initiating the process for naming a particular object or set of objects;

  3. The process should not involve any financial payment between any parties, for any purpose;

  4. The process must guarantee a wide international participation;

  5. The public names proposed in naming campaign should follow the naming rules and restrictions adopted for Minor Bodies of the Solar System, by the IAU and by the Minor Planet Center (see, or, for more details,
    In particular:

    Proposed names should be:

    • 16 characters or less in length;
    • Preferably one word;
    • Pronounceable (in some language);
    • Non-offensive;
    • Not too similar to an existing name of an astronomical object. Names already assigned to astronomical objects can be checked using the links (for galactic and extragalactic names), and the MPC database (for names).

In addition it is not allowed to propose:

   • Names of pet animals;
   • Names of a purely or principally commercial nature;
   • Names of individuals, places or events principally known for political, military or religious activities;
   • Names of living individuals.

  1. the process must be respectful of intellectual property:

    • When starting a campaign involving a list of exoplanets to be named, organisations should first obtain the formal agreement of the discoverers of the listed exoplanets; the discoverers may then participate in the process.
    • These organisations must guarantee that the adopted names resulting from their campaign are free for public use (i.e., for instance, not subject to copyright royalties, as could be the case for names created in fiction works, like books, plays, movies, etc.).

Note that organizations not prepared to follow the abovementioned rules cannot be supported by the IAU, and the names resulting from their process will not be recognized by the IAU. In particular, petitions are not considered an appropriate naming process.

Until the proposal is finalized and the process publicly started with the agreement of the IAU, the discussions between the proposing organization and the IAU must be kept strictly confidential for both parties. After concluding any public consultation, the final submission of the selected names to the IAU, and subsequent discussions with the IAU, must also be kept confidential.. 

When the organization recommends a name, or names, to the IAU, the Executive Committee Working Group Public Naming of Planets and Planetary Satellites will solicit the expertise of the relevant IAU bodies (typically, specialized Commissions and/or Working Groups), and accept input from the organization, to select the name(s) that will constitute the official IAU sanctioned name(s). The selected name(s) will be publicly announced by the IAU. 

It is understood that, if a scientific designation for the object(s) already exists, the public name will not replace it, but will be recognized by the IAU as the appropriate publicly used name for the object(s), and be publicized as such, along with due credit to the organization or individual that proposed it. This public name may then be used internationally along with, or instead of, the scientific designation, permanently and without restrictions.

Related Links

IAU General Assembly
Honolulu, 3-14 August 2015

IAU General Assembly 2015

Information Bulletin n° 112

Latest Information Bulletin

IAU e-Newsletter
Volume 2014 n° 3

Latest e-Newsletter

Subscribe to the e-Newsletter


Discuss the IAU Commission reform (Members only)


Communicating Astronomy with the Public Journal


IAU Office of Astronomy for Development

Office for Astronomy Development

IAU Office for Astronomy Outreach

Office for Astronomy Outreach

Astronomy Outreach Newsletters and Events

Outreach Newsletters

Peer-reviewed Astronomy Education Activities

Astro EDU

Astronomy for Development 
Strategic Plan 2010–2020

Strategic Plan