HD 40307g
HD 40307g
An artist's impression of the Super-Earth exoplanet HD 40307g orbiting its host star.
  • HD 40307g is 42 light years from Earth.
  • The planet orbits a small orange dwarf star which emits 75% less energy than our sun.
  • The HD 40307 system consists of six planets, HD 40307g is the outermost planet in the system.
  • The other five planets in the system orbit closer to their host star than Mercury orbits the sun.
  • HD 40307g orbits in the habitable zone, an area around a star where temperatures are warm enough to allow liquid water.
  • If HD 40307g is a rocky planet its gravity would be at least twice as strong as it is on Earth.
  • Further study of the planet is needed to determine its composition and atmospheric conditions.
  • In astronomical terms HD 40307g is relatively close to Earth, in the near future space based telescopes may be able to capture direct images of the planet.
  • The planet was discovered in October 2012 by a combined British and Dutch team of astronomers.
HD 40307g compared to earth
If HD 40307g has a rocky composition similar to Earth it would be at least twice the size.
HD 40307g Orbit
HD 40307g revolves around its host star at a distance of 56 million miles (90 million km) and takes 198 days to make one complete orbit.
HD 40307g Mass and Radius
HD 40307g has a mass of at least seven times that of Earth, a composition similar to our own planet would give HD 40307g a radius of around 1.9 times that of Earth.
HD 40307g Habitability
HD 40307g is ranked in the top ten of possible habitable planets outside our solar system. Unlike some other planets that have been detected in the habitable zone it is not tidally locked, meaning that it has a day and night, greatly enhancing the possibility of life evolving on the planet.
HD 40307g Statistics

Host Star: HD 40307
Host Star Type: Orange Dwarf - K Class
Host Star Mass: 75% of Sun
Constellation: Pictor
Distance from Earth: 42 light years
Planets Detected in System: 6
Discovery Date: October 28th 2012
Detection Method: Radial Velocity
Exoplanet Type: Super Earth

Mass: At least 7 x Earth
Diameter: Around twice that of Earth depending on composition
Distance from host star: 56 million miles (90 million km)
Orbital Period: 197.8 days
Atmosphere: Unknown
Temperature: Unknown.
Gravity: At least 2 x Earth's gravity
Possibility of Life: If HD 40307g is a rocky planet with an Earth like atmosphere it is possible forms of life may be present on the planet.