A UNSW-led team of researchers has discovered an exoplanet orbiting in the 'goldilocks zone' around a red dwarf star 16 light-years away.
The planet, GJ 832c, has a nearly-circular orbit of 16 Earth days and is a super-planet almost five times the mass of Earth. A cold jupiter-like planet was spotted orbiting the same star in 2009, with a 9.4-year orbit time, making this planetary system a simplified version of our solar system.
Of all the exoplanets discovered, it is the third most likely to harbour life, with an Earth Similarity Index (ESI) of 0.81 (Earth has an ESI of 1.00). The most likely candidate is Gliese 667C c (23 light years away) and the second is Kepler-62 (1,200 light years away).
Dr Robert Wittenmyer and his collegues at the UNSW School of Physics collaborated with an interational team of scientists to make the discovery. They have announced their findings online ahead of publication in Astrophysics Journal.
The planet is closer to its star than Earth is to the Sun but it recieves a similar amount of stellar radiation to Earth because red dwarfs emit less energy than the Sun (a yellow dwarf star).
If the planet has an atmosphere of a similar thickness to Earth, it may be possible for life to survive. However, the size of the planet suggests that it might have a thick atmosphere that would trap heat and raise temperatures beyond that tolerated by life.
The planet was initially observed using the Anglo-Australian Telescope and confirmation was made using two telescopes in Chile. The planet was discovered using the radial velocity method, which detects the small gravitational pull of the planet on the red dwarf that causes the star to 'wobble' slightly.