An article published in the journal “Astronomy & Astrophysics” reports the identification of two hot Neptunian exoplanets in the TOI-942 system. A team of researchers led by Ilaria Carleo of Wesleyan University, USA, and associated with the Italian National Institute of Astrophysics, Padua, used observations conducted with NASA’s TESS space telescope to find the exoplanet candidates, subsequently confirmed with follow-up observations conducted with the HARPS-N instrument mounted on the Galileo National Telescope, Canary Islands, and the REM instrument at the La Silla observatory, Chile. With an estimated age between 30 and 80 million years, it’s the youngest planetary system discovered thanks to TESS, excellent for studying planet evolution.
Launched on April 18, 2018, the TESS space telescope has already led to several exoplanet discoveries. At the end of 2018, its observations of the young star cataloged as TOI-942 (TOI = TESS Object of Interest) revealed traces of transits in front of it detected by TESS. The star is a bit smaller and less massive than the Sun, and about 500 light-years from Earth, an interesting object of study because young exoplanets can offer information on their phase of formation and evolution.
The data collected by the TESS space telescope were analyzed and follow-up observations were conducted with the HARPS-N instrument mounted on the Galileo National Telescope, Canary Islands, and the REM (Rapid Eye Mount) instrument at the La Silla observatory, Chile, in the course of the GAPS2 (Global Architecture of Planetary Systems 2) project, which includes most of the Italian astronomers working on exoplanets.
The combination of all the data allowed to confirm the presence of two exoplanets orbiting the star TOI-942: the closest has a year that lasts only about 4.3 Earth days while the other has a year that lasts about 10.2 Earth days. The two planets are similar in size with a radius that is 4.2 and 4.8 times the Earth’s respectively, so they’re similar to Neptune. They’re close to their star, so they fall into the hot-Neptune class.
The age of the system was estimated from the spectroscopic data obtained with the HARPS-N instrument between 30 and 80 million years, making it the youngest planetary system discovered so far thanks to the TESS space telescope. It’s very young in astronomical terms, and represents an excellent object of study to better understand the early stages of planet evolution.
Different models have been developed in this field, and each new young planetary system discovered offers new possibilities to test and refine them. In particular, the TOI-942 system offers the opportunity to study young exoplanets close to their star to try to understand whether they formed in that area or they migrated from an outer area.
Ilaria Carleo’s team will continue to study the TOI-942 system to obtain more precise data on the characteristics of the two exoplanets, starting with an estimate of their masses. New follow-up observations will be conducted using ESA’s Cheops space telescope, designed precisely for this type of research.