GJ 1132 is a small red dwarf star 41.1 light-years (12.6 parsecs) away from Earth[1] in the constellation Vela. In 2015, it was revealed to have a hot rocky Earth-sized planet orbiting it every 1.6 days.[6] In 2018, a second planet and a potential third were revealed.[4]
Planetary system
As of June 12, 2018, there are two confirmed exoplanets and one candidate exoplanet orbiting GJ 1132.
GJ 1132 b is the innermost planet of the GJ 1132 system, as well as the smallest. It is very similar in size and mass to Earth, with a radius of 1.13 R🜨 and a mass of 1.66 ME. It is slightly denser than Earth with 30% more surface gravity, meaning it has a rocky composition.[4] Despite its physical similarities to Earth, it is considered too hot to be habitable, getting 19 times more sunlight due to its 1.6 day orbital period. As of 2022[update], it remains unclear whether the planet has an atmosphere, with some studies finding evidence for an atmosphere,[7][8] but others finding a flat, featureless spectrum that leaves the presence or absence of an atmosphere inconclusive.[9][10][11]
GJ 1132 c
GJ 1132 c was reported by Bonfils and colleagues using the HARPS spectrograph on the ESO 3.6 m Telescope at the La Silla Observatory in Chile in June 2018. No transits of the planet were found, but it has a minimum mass of about 2.6 ME and gets 1.9 times the amount of sunlight as Earth with an equilibrium temperature of 300 K (27 °C; 80 °F). It orbits outside the inner limit of GJ 1132's habitable zone (which ends at 1.6 times the stellar flux of Earth), but because the exact characteristics of the planet's atmosphere are unknown, it has been mentioned that it could still be potentially habitable. However, with a lack of transits, determining its atmospheric characteristics will be extremely difficult.[4]
GJ 1132 d
An unconfirmed cold super-Earth candidate was also detected, with a minimum mass of about 8.4 ME and a low equilibrium temperature of 111 K (−162 °C; −260 °F). It has been designated GJ 1132 (d) with parenthesis because it is not considered a confirmed planet. Despite the signal having a false alarm probability of less than 0.01%, comparable to GJ 1132 b and c, it is close to the period of the star's magnetic cycle.[4]
^ abBidelman, W. P. (October 1985), "G. P. Kuiper's spectral classifications of proper-motion stars", The Astrophysical Journal Supplement Series, 59: 197–227, Bibcode:1985ApJS...59..197B, doi:10.1086/191069.