Gliese 176 b is a super-Earth exoplanet approximately 31 light years away in the constellation of Taurus. This planet orbits very close to its parent red dwarf star Gliese 176 (also called "HD 285968").
![]() Gliese 176 b, hot "Super-Earth" with hazy and dense atmosphere alike Venus | |
Discovery | |
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Discovered by | Endl,[1] Forveille et al.[2] |
Discovery date | September 7, 2007 |
Detection method | radial velocity |
Orbital characteristics | |
Semi-major axis | 0.066±0.001 AU |
Eccentricity | 0.148+0.249 −0.036 |
Orbital period (sidereal) | 8.776+0.001 −0.002 d |
Time of periastron | 2450839.760 |
Argument of periastron | 150.6+42.2 −104.5 |
Semi-amplitude | 4.49+1.00 −0.23 |
Star | Gliese 176 |
Physical characteristics | |
Temperature | ~450[2] |
The initial announcement confused the planetary periodicity with the stellar periodicity of 40 days, thus giving a 10.24 day period for a 25 Earth-mass planet.[1] Subsequent readings filtered out the star's rotation, giving a more accurate reading of the planet's orbit and minimum mass.
The planet orbits inside the inner magnetosphere of its star. The quoted temperature of 450 K is a "thermal equilibrium" temperature.[2]
It is projected to be dominated by a rocky core, but the true mass is unknown. If the orbit is oriented such that we are viewing it at a nearly face-on angle, the planet may be significantly more massive than the lower limit. If so, it may have attracted a gas envelope like Uranus or Gliese 436 b.[2]