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
Declination	−17° 46′ 24.294″
Apparent magnitude (V)	10.894
Characteristics
Evolutionary stage	Red dwarf
Spectral type	M2
U−B color index	1.155
B−V color index	1.549
V−R color index	1.018
R−I color index	1.205
J−H color index	0.553
J−K color index	0.815
Astrometry
Radial velocity (Rv)	14.55 ± 0.24 km/s
Proper motion (μ)	RA: 405.2 ± 3.1 mas/yr ; Dec.: -650.6 ± 3.2 mas/yr
Parallax (π)	80.89 ± 1.97 mas
Distance	40.3 ± 1.0 ly ; (12.4 ± 0.3 pc)
Absolute magnitude (MV)	10.48
Details
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	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]

The Gliese 180 planetary system^[8]^[9]^[10]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.02611 ± 0.00558 $M$ _J	0.103 ± 0.0008	17.38 ± 0.016	0.11 ± 0.03	—	—
с	0.02014 ± 0.00126 $M$ _J	0.129 ± 0.01	24.329 ± 0.014	0.09 ± 0.07	—	—
d	7.56 ± 1.07 $M$ _🜨	0.309 ± 0.010	106.300 ± 0.129	0.14 ± 0.04	—	—

References

^ ^a ^b 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, S2CID 18759600
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ 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
^ ^a ^b Wenger; et al. (March 2016), "GJ 180", The SIMBAD astronomical database, vol. 143, Strasbourg, France: Centre de Données astronomiques de Strasbourg, pp. 9–22, arXiv:astro-ph/0002110, Bibcode:2000A&AS..143....9W, doi:10.1051/aas:2000332, S2CID 2631342
^ ^a ^b 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, doi:10.1888/0333750888/2862
^ ^a ^b European Space Agency (1997), The Hipparcos and Tycho catalogues; astronomic and photometric star catalogues derived from the ESA Hipparcos Space Astronomy Mission, ESA SP, vol. 1200, Noordwijk, Netherlands: ESA Publications Division, Bibcode:1997ESASP1200.....E, ISBN 9290923997, OCLC 222398081
^ Turnbull, Margaret C. (October 2015), ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions, arXiv:1510.01731, Bibcode:2015arXiv151001731T
^ ^a ^b Sutherland, Paul (March 5, 2014). "Habitable planets common around red dwarf stars". Sen. Sen Corporation Ltd.
^ "Planet Gj 180 b". Extrasolar Planets Encyclopaedia. Retrieved 2014-05-25.
^ "Planet Gj 180 c". Extrasolar Planets Encyclopaedia. Retrieved 2014-05-25.
^ Feng, Fabo; Butler, R. Paul; Shectman, Stephen A.; Crane, Jeffrey D.; Vogt, Steve; Chambers, John; Jones, Hugh R. A.; Wang, Sharon Xuesong; Teske, Johanna K.; Burt, Jenn; Díaz, Matías R.; Thompson, Ian B. (2020). "Search for Nearby Earth Analogs. II. Detection of Five New Planets, Eight Planet Candidates, and Confirmation of Three Planets around Nine Nearby M Dwarfs". The Astrophysical Journal Supplement Series. 246 (1): 11. arXiv:2001.02577. Bibcode:2020ApJS..246...11F. doi:10.3847/1538-4365/ab5e7c. S2CID 210064560.{{cite journal}}: CS1 maint: unflagged free DOI (link)

Observation data Epoch J2000 Equinox J2000
A star chart of the constellation of Eridanus showing the position of Gliese 180
Constellation	Eridanus
Right ascension	04^h 53^m 49.9798^s^[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 (R_v)	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 mas^[5]
Distance	40.3 ± 1.0 ly (12.4 ± 0.3 pc)
Absolute magnitude (M_V)	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	data
ARICNS	data

References

Further reading