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Find below replies to frequently asked questions.


What is the NameExoWorlds project?

NameExoWorlds is a project carried out by the International Astronomical Union which offers the opportunity for each country to name an exoplanet and its hosting star.


What is an exoplanet?

An exoplanet is a planet outside the Solar System. They orbit stars or stellar remnants (like white dwarfs or neutron stars). Thousands of exoplanets have been discovered orbiting other stars over the past three decades. The exoplanets to be named via the IAU100 NameExoWorlds campaign are in systems with a single star and only one exoplanet known so far. Other exoplanets may be orbiting these stars, and perhaps even other stellar companions, but additional objects in these systems are not yet known.


How does this project works?

National Committees have been created to carry out the project on a national level. There are the bodies responsible for collecting proposals and submitting some of them for public voting. NameExoWorlds National Committees can apply to become a more permanent IAU National Outreach Committees.


How can I participate?​

Participants can submit proposals for naming one planet and its star through their National Committee. Every participating country will carry its own proposal submission process and voting system. Check out the information provided by the National Committee of your country in the Get involved page.


I live abroad, can I still participate?

In principle, yes, since most of the countries are carrying out online method for proposing names and for voting. Check out how your country is running the contest in the Get Involved page.


Can I submit name proposals and vote more than once?

No, you are only allowed to vote once. Please do not suggest or send names directly to the IAU100 NameExoWorlds Steering Group or other IAU Executive Committee members. Entries must be submitted through your National Committee.


What is an "exoworld"?

For the purposes of this naming campaign, the nickname “exoworld” refers to a system of an exoplanet and its host star. This project allows the public to participate in the naming of not only an exoplanet, but its host star.


What type of systems will be named?

The systems to be named are single stars with only one known planet orbiting around it. You can find more details about these “exoworlds” in the ExoWorlds page. These systems could have additional planets orbiting them, or even previously missed stellar companions (many stars are in stellar multiples with 2, or 3, or more companions), but so far these systems seem to be single stars with one known planet. The stars are visible through a small telescope. The exoplanets are all likely to be gas giants with masses between about 10% and 500% of Jupiter’s mass.


How many exoworlds will be named?

Each participating country will have the opportunity to name one star and one planet.


I can't find my country in the list. Does it mean that the country is not participating?

It may happen that some countries will join in a later stage. If your country is not listed as organiser of a national campaign, stay tuned or get in touch with us.


When will the results be released?

IAU is planning to announce the selected names in December 2019.


Will this project continue?

At this time this project is planned to be completed once all the names are published. The IAU may conduct more public naming campaigns in the future.


Will the chosen names be considered as official names?

Yes, IAU will officially recognize the chosen names. 


Will these names replace the scientific designations for these exoplanets and stars?

No, the names are in addition to the previous scientific designations, and do not replace them.


The IAU distinguishes between “designations” and “names”. Scientific designations are regularly used by astronomers in the course of studying these systems, and often include numbers (indices, celestial positions), letters (Roman, sometimes Greek), acronyms, etc., e.g. "HR 6585",  "HD 160691", "Mu Arae".


Names are proper names made up of letters, initial letters capitalized, and without numbers, e.g.  "Cervantes". All catalogued stars and exoplanets have one or more designations, but only a few hundred stars and a couple dozen exoplanets currently have names recognized by the IAU.


Read more on the IAU page on Naming of Astronomical Objects.


Are there specific rules for naming exoworlds?

Yes, there are. Check the rules in the Naming rules page.


Can I see the star that the exoplanet orbits?

Yes, the star assigned to each country is visible from that country with a small telescope during particular times of the year. The coordinates and brightness (magnitude) for each system are listed in the link given:


Wait, does the IAU have a definition for “exoplanet”? I thought the 2006 IAU definition of planet only applied to bodies in the Solar System?

The 2006 definition of planet was originally proposed to account for bodies both inside our solar system and those orbiting other stars, but astronomers were only able to agree on a resolution defining planets (and dwarf planets) in our Solar System. As planets around other stars only started being discovered about 30 years ago, and our understanding of exoplanets has been rapidly evolving as the discoveries have been made, the definition of planet applicable for those outside the Solar System has been the subject to working definitions agreed upon by IAU working groups. In 2003, IAU Division III Working Group on Extrasolar Planets (WGESP) provided a position statement (“working definition”) for planet relevant to exoplanets. Also a paper describing a new working definition and its motivation is being written by the leadership of IAU Commission F2. Note that these working definitions are not IAU Resolutions put before the General Assembly and hence need more discussion. The objects to be named in the present campaign fulfill all criteria in the working definitions to be considered as exoplanets.


Some of the countries in the list are not members of the UN?

For this project we decided to take an inclusive approach and allow all UN Members States, UN Observer States, as well as dependent territories to take part.


Will the Tau Bootis system be included in the IAU100 NameExoWorlds competition?

No. After Tau Bootis and its exoplanet were not assigned names in the 2015 NameExoWorlds campaign, it was intended that the system would be named in a future naming campaign. However the rules of the 2019 edition differ from the 2015 edition in many ways, and Tau Bootis b does not satisfy the current
conditions (especially as it is a much brighter host star). The IAU may consider
including the system in a future naming campaign.


Are names which have been used for surface features on solar system bodies (e.g.  craters on Venus, etc.) eligible to be used for names of either exoplanets or stars in the NameExoWorld campaign?

While the NameExoWorlds campaign wants to avoid duplication between the new exoplanet and star names and the names of celestial bodies previously recognized by the IAU (e.g.  exoplanets, planets, planetary satellites, small solar system bodies, etc.), duplications with the names of surface features on celestial bodies are generally acceptable. That is, “surface features” are not considered as separate “celestial bodies” for the purposes of the NameExoWorlds campaign. 


Can participants propose more than one pair of names?

This is left at the discretion of the national campaigns. However, experience suggests that more thoughtful entries come when participants are limited to a single submission (in this case, a pair of names for the exoplanet and star).


Can National Committee members propose names and/or vote?

National Committee members may vote, as other eligible participants. However, part of the price for helping organize the national naming campaigns is forfeiting the right to submit proposed names (so as to avoid perceived conflicts of interest).


Can there be separate winners for the naming of the exoplanet and its host star?

The submissions should be *pairs* of names (one for the exoplanet, one for the host star), following a stated common naming theme (ideally a theme that could be drawn upon for additional names should additional objects in that system be discovered in the future). So ideally, the pair names are attributable to the same participant. However there may be instances where the National Committee feels that a merging of entries would result in an improved pair of names and naming theme, so such cases may be considered by the Steering Committee.


Is [name of character from recent popular movie, cartoon, TV show, comic book, etc. that is protected by intellectual property rights] eligible to be used for naming an exoplanet or its star?

No. Please keep in mind the following guidelines: “The proposed names should be of things, people, or places of long-standing cultural, historical, or geographical significance, worthy of being assigned to a celestial object”,  and excluded are “names of a purely or principally commercial nature” and  “names that are principally known as trademarks or protected by intellectual property claims.” If a character is in a famous recent film, show, comic book, etc., chances are that its use is protected by intellectual property claims, and hence are ineligible to be used for naming in this campaign. Generally, names and places from very old works tend to be in the public domain, and hence eligible for use as names.


What if permission is given by the owner of an intellectual property claim (e.g. trademark) for the name to be used for naming of an exoplanet or its star?

For the IAU NameExoWorlds campaign, it has been decided to avoid the adoption of “names that are principally known as trademarks or protected by intellectual property claims” for exoplanets and their host stars, even in cases where permission has been given for their use.


What if the winning name comes from more than one person?

We will try to credit as many of the proposers of the winning names as possible, however we may name either the person who proposed the entry first, or who provided the most comprehensive citation, as the first name listed.

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