Gliese 176 b

Gliese 176 b
	Gliese 176 b, hot "Super-Earth" with hazy and dense atmosphere alike Venus
Discovery
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	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]

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").

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]

References

Endl, Michael; et al. (2008). "An m sin i = 24 M_⊕ Planetary Companion to the Nearby M Dwarf GJ 176". The Astrophysical Journal. 673 (2): 1165–1168. arXiv:0709.0944. Bibcode:2008ApJ...673.1165E. doi:10.1086/524703.
Forveille, T.; et al. (2009). "The HARPS search for southern extra-solar planets. XIV. Gl 176b, a super-Earth rather than a Neptune, and at a different period". Astronomy and Astrophysics. 493 (2): 645–650. arXiv:0809.0750. Bibcode:2009A&A...493..645F. doi:10.1051/0004-6361:200810557.

External links

"Notes for planet HD 285968 b". The Extrasolar Planets Encyclopaedia. Archived from the original on 2010-04-07.
"HD 285968". Exoplanets. Archived from the original on 2012-02-12. Retrieved 2008-08-02.

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[Endl2008-1] Endl, Michael; et al. (2008). "An m sin i = 24 M_⊕ Planetary Companion to the Nearby M Dwarf GJ 176". The Astrophysical Journal. 673 (2): 1165–1168. arXiv:0709.0944. Bibcode:2008ApJ...673.1165E. doi:10.1086/524703.

[Forveille2009-2] Forveille, T.; et al. (2009). "The HARPS search for southern extra-solar planets. XIV. Gl 176b, a super-Earth rather than a Neptune, and at a different period". Astronomy and Astrophysics. 493 (2): 645–650. arXiv:0809.0750. Bibcode:2009A&A...493..645F. doi:10.1051/0004-6361:200810557.