Gliese 180

Gliese 180

A star chart of the constellation of Eridanus showing the position of Gliese 180
Observation data Epoch J2000      Equinox J2000
Constellation	Eridanus
Right ascension	04h 53m 49.9798s[1]
Declination	−17° 46′ 24.294″[1]
Apparent magnitude (V)	10.894[2]
Characteristics
Evolutionary stage	Red dwarf
Spectral type	M2[2]
U−B color index	1.155[2]
B−V color index	1.549[2]
V−R color index	1.018[2]
R−I color index	1.205[2]
J−H color index	0.553[2]
J−K color index	0.815[2]
Astrometry
Radial velocity (Rv)	14.55 ± 0.24[3] km/s
Proper motion (μ)	RA: 405.2 ± 3.1[4] mas/yr Dec.: -650.6 ± 3.2[4] mas/yr
Parallax (π)	80.89 ± 1.97[5] mas
Distance	40.3 ± 1.0 ly (12.4 ± 0.3 pc)
Absolute magnitude (MV)	10.48[2]
Details[6]
Mass	0.39 M☉
Radius	0.42 R☉
Temperature	3562 K
Other designations
LHS 1712, CSI-17-04516, HIC 22762, HIP 22762, LFT 377, L 736-30, LP 776-27, LPM  198, LTT 2116, 2MASS J04534995-1746235, NLTT 14144, PLX 1097, PLX 1097.00, TYC 5903-680-1, [RHG95] 838
Database references
SIMBAD	data
Exoplanet Archive	[http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=GJ 180 data]
ARICNS	data

Gliese  180 (often shortened to GJ 180), is a red dwarf star, known to have two planets Gliese 180 b and Gliese 180 c.^[3] It is located approximately 40 light-years away from Earth.^[5]

According to the Planetary Habitability Laboratory (PHL) in Puerto Rico, both worlds in the system may be classifiable as potentially habitable planets. Planet Gliese 180 b and Gliese 180 c have masses of 6.4 and 8.3 Earth masses, respectively.^[7] However, Dr Mikko Tuomi, of the UK’s University of Hertfordshire, whose team identified the planets, disagreed, stating:

"The PHL adds some sort of an “extended HZ”, which I, frankly, do not know how it’s calculated, but that adds some areas of potential habitability to the inner and outer edges of the HZ as we have defined it. They included the inner companion of the GJ 180 system (planet b) that we consider too hot to be potentially habitable.”^[7]

External Resources

• Mikko Tuomi, Hugh R. A. Jones, John R. Barnes, Guillem Anglada-Escudé, James S. Jenkins, Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics, arxiv.org, 3 March 2014.

References

1. 1 2 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
2. 1 2 3 4 5 6 7 8 9 Koen, C.; Kilkenny, D.; van Wyk, F.; Marang, F. (April 21, 2010), "UBV(RI)_CJHK observations of Hipparcos-selected nearby stars", Monthly Notices of the Royal Astronomical Society, 403 (4): 1949–1968, Bibcode:2010MNRAS.403.1949K, doi:10.1111/j.1365-2966.2009.16182.x 
3. 1 2 Wenger; et al. (March 2016), "GJ 180", The SIMBAD astronomical database, Strasbourg, France: Centre de Données astronomiques de Strasbourg, arXiv:astro-ph/0002110, Bibcode:2000A&AS..143....9W, doi:10.1051/aas:2000332 
4. 1 2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355 (2): L27–L30, Bibcode:2000A&A...355L..27H 
5. 1 2 European Space Agency (1997), The Hipparcos and Tycho catalogues; astronomic and photometric star catalogues derived from the ESA Hipparcos Space Astronomy Mission, ESA SP, 1200, Noordwijk, Netherlands: ESA Publications Division, Bibcode:1997HIP...C......0E, ISBN 9290923997, OCLC 222398081 
6. ↑ Turnbull, Margaret C. (October 2015), ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions, arXiv:1510.01731, Bibcode:2015arXiv151001731T 
7. 1 2 Sutherland, Paul (March 5, 2014). "Habitable planets common around red dwarf stars". Sen. Sen Corporation Ltd. 
8. ↑ "Planet Gj 180 b". Extrasolar Planets Encyclopaedia. Retrieved 2014-05-25. 
9. ↑ "Planet Gj 180 c". Extrasolar Planets Encyclopaedia. Retrieved 2014-05-25.