Using NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers have discovered two new young planetary systems. They found that two stars not older than 320 million years, namely TOI-251 and TOI-942, are orbited by a mini-Neptune planet and two Neptune-sized exoplanets. The finding is reported in a paper published November 26 on arXiv.org.

TESS is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. So far, it has identified over 2,400 candidate exoplanets (TESS Objects of Interest, or TOI), of which 82 have been confirmed so far.

Recently, a team of astronomers led by George Zhou of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, confirmed another three planets. Between August and December 2018, TESS observed two stars: TIC 224225541 (TOI-251) and TIC 146520535 (TOI-942), which resulted in the detection of transit signals in the light curves of these objects. The planetary nature of these signals was confirmed by follow-up photometric and spectroscopic observations using ground-based facilities.