NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered a Super-Earth among other additional worlds orbiting the same star, with the former located in the star’s habitable zone. If made of rock, this planet may be around twice Earth’s size. It’s named GJ 357, an M-type dwarf about one-third the Sun’s mass and size and about 40% cooler that our star. The system itself is located 31 light-years away in the constellation Hydra. TESS cameras captured the star dimming slightly every 3.9 days back in February, which reveals the presence of a transiting exoplanet that passes across the face of its star during every orbit and briefly dims the star’s light. Read more for a video and additional information.
The transits that NASA’s TESS observed belong to GJ 357 b, a planet about 22% larger than Earth. It orbits 11 times closer to its star than Mercury does our Sun, which means it has an equilibrium temperature — calculated without accounting for the additional warming effects of a possible atmosphere — of around 490° Fahrenheit.
“We describe GJ 357 b as a ‘hot Earth,’…Although it cannot host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess,” said o-author Enric Pallé, an astrophysicist at the IAC and Luque’s doctoral supervisor.