Distant 'cold Earth' candidate HD 137010b teeters on the edge of its star's habitable zone
Astronomers analyzing Kepler/K2 data have identified a possible rocky exoplanet, HD 137010b, orbiting a K-type dwarf about 146 light-years away. It is expected to be about 1.06 times the diameter of Earth and complete an orbit roughly every 355 days, receiving around 29% of the Sun-like energy Earth gets. This places it at the outer edge of the star’s habitable zone, meaning its surface could be frozen unless it has a thick atmosphere. Only one transit has been observed, so the planet’s existence and exact conditions remain unconfirmed, but future observations by missions such as CHEOPS, TESS, PLATO, and JWST could help determine its reality and assess any atmosphere. The discovery paper notes a 40% chance of being in the conservative HZ, a 51% chance in the optimistic HZ, and a 50/50 chance of not being in the HZ at all.