Proxima Centauri c, also known as Proxima c, or Alpha Centauri Cc, is a super-Earth extrasolar planet candidate orbiting the red dwarf star Proxima Centauri, the closest star to the Sun, located around 4.24 light years away from Earth in the constellation of Centaurus. It is one of the closest extrasolar planets found, alongside Proxima Centauri b and d, and is the second planet discovered in the system.
Proxima Centauri c has an orbital period of around 1928 days, or 5.27 years, and orbits at a distance of around 1.5 times that of Earth to the Sun. It has a mass of about 7 times that of Earth, and is either a super-Earth or mini-Neptune.[1] The planet is extremely frigid and uninhabitable, due to its great distance from its star, and has a low equilibrium temperature of 39 K (-234 °C; -389 °F), making it one of the coldest extrasolar planets ever found.
A study in 2022 questioned the planetary nature of the observed radial velocity signal corresponding to Proxima c, and attributed it to systematic effects; it is unclear, however, why astrometric observations detected what appeared to be a similar planetary signature.
Possible ring system[]
In June 2020, a possible direct imaging detection of Proxima Centauri c was published. It was determined that the planet had an unusual brightness for a planet of its mass and age, which implies the planet may have a ring system, with a radius of around 5 Jupiter radii.[2]