Scientists from the National Autonomous University of Mexico (UNAM) participated in the discovery of the second Earth-sized exoplanet, which orbits an ultracold dwarf star. Yilen Gómez Maqueo Chew, Laurence Sabin, and Ilse Plauchu-Frayn, scientists at the Institute of Astronomy, collaborated in the discovery of SPECULOOS-3b using the Swiss-Mexican Telescope SAINT-EX and the SPECULOOS network.
Gómez Maqueo Chew mentioned that this discovery is significant because it is only the second planetary system found around an ultracold dwarf star, with the first being TRAPPIST-1 discovered in 2016. The newly found exoplanet, SPECULOOS-3b, is close in size to Earth with a radius of 0.977, similar to the Moon. It has a fixed rotation period of 17 hours and orbits its star in the same amount of time.
The scientists used the transit method to detect the exoplanet, measuring the decrease in the star’s luminosity to indicate the presence of an orbiting object. They encountered challenges in identifying the transits due to their limited measurability. Further observations in 2022 and 2023 confirmed the presence of the exoplanet.
The mass of SPECULOOS-3b remains unknown, which is crucial in determining its density. It was noted that ultracold dwarf stars are highly active magnetically, causing objects close to them to lose their atmosphere due to constant radiation and particles. The discovery was published in the journal Nature Astronomy, showcasing the importance of continuing research to understand the diversity of exoplanets around ultracool dwarf stars.