Proxima Centauri

Designation: //
Hemisphere: Southern
Constellation: Centaurus
Distance: 4.2 light years
Object type: Red dwarf star


Discovered in 1915 by Robert Innes, Proxima Centauri is a small, low-mass star in the southern constellation Centaurus, the Centaur. At a distance of only 4.2 light years, Proxima Centauri is the closest star to the Sun (“Proxima” is Latin for “nearest”) but despite that, it is not visible to the naked eye due to its small size and low magnitude. Astronomers estimate that Proxima is roughly one eighth of our Sun’s mass, and 500 times less bright.

Proxima is a member of the Alpha Centauri star system, which is home to three known stars, and in which is identified as Alpha Centauri C along the Alpha Centauri AB pair. So far, astronomer have discovered three exoplanets orbiting Proxima:

  • Proxima b: a planet with 1.3 times the mass of Earth orbiting within the habitable zone, at a distance of roughly 7.5 million km (4.7 million miles), with an orbital period of approximately 11.2 Earth days.
  • Proxima c: a super-Earth or mini-Neptune planet, about 7 times as massive as Earth, that orbits its star every 1,907 days at a distance of about 1.5 times the distance that separates Earth from the Sun.
  • Proxima d: the least massive and innermost known planet of the Proxima Centauri, at least one-quarter of the mass of Earth (or twice the mass of Mars). It orbits its star every 5.1 days at roughly 4.3 million km (2.7 million miles).

While Proxima b is within the habitable zone, it is thought that none of the planets around Proxima Centauri can host life. This is because Proxima Centuari is known as a “flare star2, emitting random and dramatic, massive flares, which might make life as we know it impossible.

Acquisition details

Total integration time: 2 hours 10 minutes
Acquisition software: AUS-2 (Telescope Live)
Processing software: PixInsight
Location: Australia

Full size image

Where the universe begins…