Alpha Centauri Bb
Alpha Centauri Bb
Artist's impression of the exoplanet Centauri Bb, the bright star on the top right is our sun.
  • Alpha Centauri Bb is an unconfirmed exoplanet that orbits around the sun like star Alpha Centauri B.
  • At only 4 light years from Earth it is the closest planet ever detected outside our solar system.
  • Alpha Centauri is the closest star system to the sun and consists of the sun like Alpha Centauri A and B plus the red dwarf Proxima Centauri.
  • Surface temperatures on the planet are estimated to be around 1200C (2192F), which is almost three times hotter than Venus.
  • Alpha Centauri Bb is probably tidally locked, meaning that the same side of the planet is always facing its host star.
  • It is highly unlikely that any form of life could exist in the planet's harsh conditions.
  • It is possible that other small rocky planets orbit around the habitable zone of the star but they have yet to be detected.
  • Even though the Alpha Centauri system is relatively close to Earth it would still take a conventional spacecraft 50,000 years to reach it.
lava world
Many areas of Alpha Centauri Bb would be so hot its surface would exist as molten lava.
Alpha Centauri Bb Orbit
Alpha Centauri Bb revolves around its host star at a distance of only 3.7 million miles (6 million km), 10 times closer than Mercury orbits the sun, as a result of its close proximity it takes only 3 days to make one complete orbit.
Alpha Centauri Bb Mass and Radius
Alpha Centauri Bb is estimated to have a mass around the same as that of Earth, its radius is unknown but it is possible it's around the same size as our own planet.
Alpha Centauri Bb Atmosphere
The planet's tenuous atmosphere would be mostly composed of carbon dioxide and sulfur dioxide given off by the planet's molten lava surface, this atmosphere would constantly be being blasted away by its host star.
Alpha Centauri Bb Statistics

Host Star: Alpha Centauri B
Host Star Type: Orange Dwarf - K Type Main Sequence
Host Star Mass: 90% of Sun
Constellation: Centaurus

Distance from Earth: 4 light years
Planets Detected in System: 1 unconfirmed

Discovery Date: October 2012
Detection Method: Radial Velocity
Exoplanet Type: Super Earth

Mass: 1.13 x Earth
Diameter: Unknown, possibly similar to Earth depending on composition

Distance from host star: 3.7 million miles (6 million km)
Orbital Period: 3.2 days

Atmosphere: Probably tenuous, mostly composed of carbon dioxide, sulfur dioxide
Temperature: Surface temperatures of around 1200C (2192F)
Gravity: Possibly similar to Earth

Possibility of Life: None