Within the framework of its 100th anniversary commemorations, the International Astronomical Union (IAU) is organising the IAU100 NameExoWorlds global competition that allows any country in the world to give a popular name to a selected exoplanet and its host star. Exoplanet rendering by IAU.

Four years ago, the International Astronomical Union organized a competition to give popular names to 14 stars and 31 exoplanets that orbit them.  The event encouraged 570,000 people to vote and the iconic planet 51 Pegasi b became “Dimidium, ” 55 Cancri b became “Galileo,” and (among others) Formalhaut b became “Dagon.”

It remains unclear how often those popular names are used in either scientific papers or writing about the papers.  But the idea of giving mythical names, names that describe something unique about the planet (or star)  or that nod to famous astronomer or iconic writers has caught on and the IAU has a new naming contest up and running.

This one is the IAU NameExoWorlds global campaign, and almost 100 nations have signed up to organize public national campaigns that will  give new names to a selected exoplanet and its host star.

“This exciting event invites everyone worldwide to think about their collective place in the universe, while stimulating creativity and global citizenship,” shared Debra Elmegreen, IAU President Elect. “The NameExoWorlds initiative reminds us that we are all together under one sky.”

From a large sample of well-studied, confirmed exoplanets and their host stars, the IAU NameExoWorlds Steering Committee assigned a star-planet system to each country, taking into account associations with the country and the visibility of the host star from most of the country.

The national campaigns will be carried out from June to November 2019 and, after final validation by that NameExoWorlds Steering Committee, the global results will be announced in December 2019. The winning names will be used freely in parallel with the existing technical scientific names.

The bulge of the Milky Way, as imaged by the Hubble Space Telescope. Our galaxy is inferred to have hundreds of billions of stars, and even more planets. (NASA, ESA, and T. Brown (STScI);


The naming contest flows from the well-established fact that exoplanets are everywhere — at least one around most stars, scientists have concluded.  Some 4,500 exoplanets have been identified so far, but this is but the beginning.  Astronomers are confident there are hundreds of billions of exoplanets — ranging from small and rocky like Earth to massive gas giants much larger than Jupiter — in our galaxy reaches into the many billions.

Thus far,  the known exoplanets remain largely in the realm of technical space science.  The NameExoWorlds campaign is an effort to make some of the exoplanets (and their host stars) part of a broader public discussion.  Maybe not on a par with Jupiter or Mercury or that IAU downgraded “dwarf planet” Pluto, but more familiar than WASP21 b or HD 86081 b or HAT-P-3 b.  (The “b” or “c” ore “d” after the scientific description of the star describes a planet and how close to the host star it orbits, with “b” the closest._

The contest is being held now as part of the 100th anniversary of the IAU,  an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy.

Among other activities, the IAU acts as the internationally recognized authority for assigning designations and names to celestial bodies (stars, planets, asteroids) and any surface features on them.  Getting the public involved in some of the non-scientific naming was a central goal of the initial exo-worlds naming contest, the 2015 campaign to rename a relative handful of exoplanets and host stars.

Infographic displaying a breakdown of the winning names and brief descriptions of the chosen names. As announced in December 2015, names for 31 exoplanets and 14 host stars, voted for by the public, were accepted and were officially sanctioned by the IAU.

Within the framework of the IAU100 NameExoWorlds project , every country has the opportunity chance to name one planetary system, comprising an exoplanet and its host star.  Each nation’s designated star is visible from that country, and sufficiently bright to be observed through small telescopes.

Here is the list of stars and exoplanets, with their constellation and locations,  assigned to participating nations:  http://www.nameexoworlds.iau.org/list-of-stars

In each participating country, a team of National Outreach Coordinators (IAU NOCs) has been  create to carry out the campaign at the national level. The national committee, following the methodology (http://nameexoworlds.iau.org/methodology) and guidelines (http://nameexoworlds.iau.org/naming-rules) set up by the IAU100 Name ExoWorlds Steering Committee, is the body responsible for providing the conditions for public participation, disseminating the project in the country and establishing a voting system.

In the earlier 2015 naming contest,  these are some of the winners.

From Spain, all in the Mu Area system: Cervantes, Quijote, Dulcinea, Rocinante, Sancho

From the United States: Ran, AEgir and Dagon

From Thailand: Taphao and Thong

From Italy:  Draugr, Poltergeist and Phobetor.

From Japan:  Amateru, Arion, Arkas and Fortitudo

From the Netherland, all in th 55 Cancri system:  Galileo, Brahe, Lippershey, Janssen and Harriot

In nations that have not organized a national campaign, science organization and Non-Governmental Organization interested in carrying out a nation-wide contest, have until 30 July 2019 to express interest to (http://nameexoworlds.iau.org/get-involved).

The planets in our solar system were named as they were discovered, mostly after Roman gods.  Uranus (a Greek god) and Earth (derived from the English/German word “ertha” for “ground”) are the exceptions.

With so many billions of exoplanets, a different naming protocol was clearly needed.  But the aim is pretty much the same:  To make distant celestial bodies a more identifiable and intimate part of our human world.