At the end of December 2019, the names of over 110 exoplanets and their host stars selected in the IAU100 NameExoWorlds campaign were announced at a press conference in Paris (France). Within the framework of the International Astronomical Union’s 100th anniversary celebrations in 2019, 112 countries, including Romania, organised national campaigns that triggered the direct participation of over 780 000 people worldwide, who proposed and selected names for each exoplanet and its host star.
The IAU100 NameExoWorlds project saw massive and widespread participation around the world, as the public eagerly engaged in this exciting opportunity to suggest meaningful, creative and unique names for exoplanet systems thtat had been allocated to their respective countries. This is only the second time in history that an official IAU campaign to name stars and exoplanets was organised. Overall, 360 000 proposals for names were received from over 110 countries. The National Committee in each country down selected their proposals to a shortlist of national candidates, which were presented to the public for voting. A total of 420 000 people voted for their preferred candidates. This project will have a lasting impact, as the winning names will be used in parallel with the existing scientific nomenclature, credited to the person, group or institution that suggested them.
The IAU100 NameExoWorlds global project was conceived to create awareness of our place in the Universe and to reflect on how the Earth would potentially be perceived by a civilisation on another planet. As the IAU is the authority responsible for assigning official designations and names to celestial bodies, the IAU100 celebrations in 2019 were used as a special occasion to offer every country the chance to name one planetary system, consisting of an exoplanet and its host star.
Romania, as a founding member of the IAU, joined this global project. Thus, between 5 August and 5 October 2019, Romanians were invited to propose names for the exoplanetary system XO-1. This system consists of the star XO-1 and its planet XO-1 b, and can be found at a distance of 536 light years, in the constellation Corona Borealis. The star is very similar to our own Sun, both in its yellow colour (given by its surface temperature), as well as in dimension, mass and total luminosity. Despite these physical resemblances, the XO-1 star is 1 billion years of age, over four times younger than our Sun.
As far as we know to date, the planet XO-1 b is the only planet orbiting the XO-1 star. It was discovered in 2006 by a team of amateur and professional astronomers, led by Peter R. McCullough. A year on the XO-1 b planet lasts almost 4 Earth days (3.94) and its average radius is 1,21 larger than Jupiter’s. Spectroscopic observations have revealed that the atmosphere of XO-1 b is rich in H2/He, containing water, molecules carrying NH3 and HCN and it has cloud patches.
Over 180 names were proposed for the XO-1 exoplanetary system. Of these, the National Committee prepared a short list of 12 nominations (this list can be found here) that were submitted to a public vote between 16 October – 3 November 2019. The winning names of the campaign were: “Moldoveanu” for the star and “Negoiu” for the exoplanet. The proposal came from Mr. Tudor Ioan Cătălin.
The IAU is the international astronomical organisation that brings together more than 13 500 professional astronomers from more than 100 countries worldwide. Its mission is to promote and safeguard astronomy in all its aspects, including research, communication, education and development, through international cooperation. The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and their surface features. Founded in 1919, the IAU is the world’s largest professional body for astronomers.