LTT 1445


LTT 1445 is a triple M-dwarf system about 22 light-years distant in the constellation Eridanus. The primary LTT 1445 A hosts one exoplanet that transits the star every five days. As of August 2019 it is the second closest transiting exoplanet system discovered, with the closest being HD 219134 bc.

Stellar system

All three stars in the system are M-dwarfs, with masses between 0.16 and 0.26. LTT 1445 A and LTT 1445 BC are separated by about 34 astronomical units and orbit each other with a period of about 250 years. The BC pair orbit each other about every 36 years in an eccentric orbit. The alignment of the three stars and the edge-on orbit of the BC pair is suggesting a co-planarity of the system. The existence of a transiting planet LTT 1445Ab suggests that the entire system is co-planar, with orbits in one plane.
The TESS light curve showed stellar flares and rotational modulation due to starspots, likely on either the B or C component.

Planetary system

was discovered in August 2019 with data from the Transiting Exoplanet Survey Satellite by astrophysicists of the Harvard Center for Astrophysics. The team obtained follow-up observations, including HARPS radial velocity measurements to constrain the mass of the planet. The planet orbits only one host star in a stable orbit. The planet likely has a rocky composition and because it orbits close to the M-dwarf, it has an equilibrium temperature of Kelvin.