Teegarden's Star Has Two Potentially Habitable Planets Orbiting

A pair of potentially habitable exoplanets have been discovered orbing around Teegarden's star. Teegarden is an old red dwarf star that is 12 light-years away from Earth in the Aries constellation. Both of the planets orbiting the star have minimum masses similar to Earth and orbit within the star's habitable zone.Teegarden's Star is the 24th nearest star to our Solar System and is the fourth closest with potentially habitable planets. It sits directly behind Proxima Centauri, Tau Ceti, and Luyten's Star. Teegarden's Star is the closest with multiple small planets in the habitable zones with similar insolations as Earth and Mars.

Scientists say that the innermost planet, Teegarden b has a 60% chance of having a temperate surface environment with a temperature between 0 and 50C. Surface temperatures should be close to 28C but could be higher or lower depending on its composition. The planet is also the planet with the highest Earth Similarity Index (ESI) discovered so far.

This means that it has the closest mass and insolation to terrestrial values. Scientists admit that they only know its minimum mass. The big mystery with these planets is that they orbit a red dwarf star. These stars are known to emit strong flares that can erode atmospheres of planets during their lifetime. Teegarden b is thought to be tidally locked and could be devoid of an atmosphere or water depending on the thermal evolution.

Teegarden c has only a 3% chance of a temperate environment on its surface. Scientists believe it is -47C assuming a terrestrial atmosphere, similar to temperatures on Mars. Both of these planets are now part of the Habitable Exoplanets catalog and are part of 18 recently discovered planets by the K2 mission.