Proxima Centauri
Proxima Centauri is a red dwarf in the Alpha Centauri system, about 4.24 light-years from Earth. It is the nearest known star to the Sun.
Red dwarf: A small, cool, low-mass star that burns hydrogen slowly and can remain on the main sequence for trillions of years. Proxima’s low mass and cool surface place it in this long-lived stellar class.
Proxima Centauri b: An approximately Earth-mass planet orbiting Proxima Centauri within the star’s temperate zone. Its orbit produces the best-known radial-velocity signal from Proxima.
Proxima Centauri c: A candidate planet reported in 2020 on a long-period orbit around Proxima Centauri. Its proposed orbit would make it a more distant companion than Proxima b.
Alpha Centauri A: A Sun-like star and the brighter primary member of the Alpha Centauri binary. Unlike faint Proxima, Alpha Centauri A is a more massive, Sun-like star.
Alpha Centauri: The nearest stellar system to the Sun, containing the binary stars Alpha Centauri A and B and the red dwarf Proxima Centauri. Proxima belongs to this system, though its orbit around the pair is wide and uncertain.
Radial velocity method: A planet-detection technique that measures periodic shifts in a star’s spectrum caused by its motion toward and away from Earth. This method revealed the recurring stellar wobble associated with Proxima b.
Proxima Centauri d: A small planet candidate reported in 2022 on a very short-period orbit around Proxima Centauri. Its signal suggests an additional, close-in planet in the system.
Alpha Centauri B: An orange dwarf star orbiting Alpha Centauri A as part of the nearest stellar binary to the Sun. Its warmer, more massive nature contrasts with Proxima’s cool red-dwarf classification.
Stellar parallax: The apparent shift of a nearby star against distant background stars as Earth orbits the Sun, used to measure distance. Parallax measurements establish Proxima’s distance from Earth.
Magnetic reconnection: A process in which oppositely directed magnetic fields reconnect, converting magnetic energy into particle motion and heat. Reconnection helps power the star’s energetic flares.