Gliese 176 b

Gliese 176 b
Exoplanet List of exoplanets
Parent star
Star Gliese 176
Constellation Taurus
Right ascension (α) 04h 42m 55.7749s[1]
Declination (δ) +18° 57′ 29.399″[1]
Distance30.7±0.2[1] ly
(9.41±0.05[1] pc)
Spectral type M2.5V
Orbital elements
Semi-major axis(a) 0.066±0.001[2] AU
Eccentricity (e) 0.148+0.249
−0.036
Orbital period(P) 8.776+0.001
−0.002 d
Argument of
periastron		 (ω) 150.6+42.2
−104.5°
Time of periastron (T0) 2450839.760 JD
Semi-amplitude (K) 4.49+1.00
−0.23 m/s
Physical characteristics
Minimum mass(m sin i)9.06+1.54
−0.70[2] M⊕
Temperature (T) ~450[3]
Discovery information
Discovery date September 7, 2007
Discoverer(s) Endl[4], Forveille et al.[3]
Discovery method radial velocity
Discovery status Published

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.[4] 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.[3]

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.[3]

References

  1. 1 2 3 4 Brown, A. G. A.; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy and Astrophysics. 595. A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. Gaia Data Release 1 catalog entry
  2. 1 2 Trifonov, T.; et al. (2018). "The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems". Astronomy and Astrophysics. 609. A117. arXiv:1710.01595. Bibcode:2018A&A...609A.117T. doi:10.1051/0004-6361/201731442.
  3. 1 2 3 4 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.
  4. 1 2 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.
  • "Notes for planet HD 285968 b". The Extrasolar Planets Encyclopaedia. Archived from the original on 2010-04-07.
  • "HD 285968". Exoplanets.

Coordinates: 04h 42m 55.7768s, +18° 57′ 29.417″

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