An exoplanet roughly the size of Neptune passes through the M3 dwarf NLTT 24399. It was named TOI-1231 b. The object was discovered using photometric data from the transit exoplanet observing satellite (TESS), as well as the Planet Finder spectrograph (PFS).
PFS is a sophisticated instrument that detects exoplanets through their gravitational effects on host stars. As the planets revolve around their hosts, the stellar velocity changes periodically, revealing the presence of the planets and information about their mass and orbit.
The object has a 24-day orbital period and orbits the nearest dwarf star M3 NLTT 24399. The authors suggested that the exoplanet has a gaseous atmosphere as large as Neptune. The temperature is similar to that of the Earth, thanks to the colder and less bright host star.
According to preliminary data, the temperature of the object is about 60 ° C: TOI-1231b is one of the coolest small exoplanets on which atmospheric research can be carried out. The low density of TOI 1231b indicates that it is surrounded by a dense atmosphere and is not a rocky planet.
Past research suggests that planets with these temperatures can have clouds in their atmosphere, which can make it difficult to determine what types of gases surround them.