It has been called "one of the most important planets ever discovered beyond the Solar System": Due to its relative proximity to Earth, telescopes should be able to determine the composition of its atmosphere, the speed of its winds and the color of its sunsets.[8][9][10] This is due in part to the small diameter of its parent star (20% that of the Sun), which increases the effect on the star's light of its transits. The planet's diameter is approximately 20% larger than that of the Earth[1] and its mass is estimated at 1.6 times that of Earth,[2] implying that it has an Earth-like rocky composition.[11] GJ 1132 b orbits its star every 1.6 days at a distance of 1.4 million miles (2.24 million kilometres).[7]
The planet receives 19 times more stellar radiation than Earth.[1] The equilibrium temperature is estimated at 529 K (256 °C; 493 °F) for an Earth-like albedo, or 409 K (136 °C; 277 °F) for a Venus-like albedo. The planet is likely to be hotter than Venus, as higher temperatures likely prevail at the surface if the planet has an atmosphere.[11]
Atmosphere
In April 2017, a hydrogen-dominated atmosphere was claimed to have been detected around GJ 1132 b.[12][6] However, subsequent, more precise work ruled out the claim.[13] Instead, in 2021 detection of a hazy hydrogen atmosphere without helium but with the admixture methane and hydrogen cyanide (implying substantial underlying free nitrogen in the mix, at around 8.9% of the atmosphere) was claimed.[14] However, two subsequent studies found no evidence for molecular absorption in the HST WFC3 Spectrum of GJ 1132 b. Instead, the spectrum was found to be flat,[15][16] which is more consistent with our current understanding of photoevaporation.[citation needed]