GJ 1214

GJ 1214

GJ 1214 is a M-class dwarf star
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 17h 15m 18.94s
Declination +04° 57′ 49.7″
Apparent magnitude (V) 14.67[1]
Characteristics
Spectral type M4.5[1]
Apparent magnitude (B) 16.40
Apparent magnitude (R) 13.8
Apparent magnitude (I) 11.1
Apparent magnitude (J) 9.75
Apparent magnitude (H) 9.09
Apparent magnitude (K) 8.78
B−V color index 1.73
V−R color index 0.9
R−I color index 2.7
Variable type planetary transit
Astrometry
Proper motion (μ) RA: 585 mas/yr
Dec.: -752 mas/yr
Distance 42.38 ly
(13 pc)
Absolute magnitude (MV) 14.10
Details
Mass 0.157 ± 0.019[2] M☉
Radius 0.211 ± 0.0097[2] R☉
Surface gravity (log g) 4.15
Luminosity 0.00328[2] L☉
Temperature 3,026 ± 130[2] K
Metallicity 0.39 ± 0.15[3].
Age 6 Gyr
Other designations
LHS 3275, GJ 1214, NLTT 44431

USNO 256, GEN# +9.80139021,
LSPM J1715+0457, UBV M 53793,
[RHG95] 2724, G 139-21,
2MASS J17151894+0457496,

USNO-B1.0 0949-00280047.[1]
Database references
SIMBAD data
NStED data
ARICNS data
Extrasolar Planets
Encyclopaedia		 data

GJ 1214 (Gliese-Jahreiss 1214) is a dim M4.5[1] red dwarf in the constellation Ophiuchus with an apparent magnitude of 14.7.[1] It is located at a distance of approximately 40 light years from Earth. It is about one-fifth as large as the Sun[4] with a surface temperature estimated to be 3,000 K (2,730 °C; 4,940 °F)[4]. Its luminosity is only 0.3% that of the Sun.[4]

The estimate for the stellar radius is 15% larger than predicted by theoretical models.[2]

Contents

Planetary system

In mid-December 2009, a team of Harvard-Smithsonian astronomers announced the discovery of a companion extrasolar planet, GJ 1214 b, potentially composed largely of water and having the mass and diameter of a super-Earth.[2][4]

The GJ 1214 system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity
b 0.0179 ± 0.0027 MJ 0.0143 ± 0.0019 1.5803925 ± 0.0000117 <0.27

Discovered by the MEarth project and investigated further by the HARPS spectrograph on ESO’s 3.6-metre telescope at La Silla, GJ1214b is the second super-Earth exoplanet for which astronomers have determined the mass and radius, giving vital clues about its structure. It is also the first super-Earth around which an atmosphere has been found.

References

  1. ^ a b c d e "LHS 3275 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=GJ+1214. Retrieved 2009-12-16. 
  2. ^ a b c d e f g Charbonneau, David; Zachory K. Berta, Jonathan Irwin, Christopher J. Burke, Philip Nutzman, Lars A. Buchhave, Christophe Lovis, Xavier Bonfils, David W. Latham, Stéphane Udry, Ruth A. Murray-Clay, Matthew J. Holman, Emilio E. Falco, Joshua N. Winn, Didier Queloz, Francesco Pepe, Michel Mayor, Xavier Delfosse, Thierry Forveille (2009). "A super-Earth transiting a nearby low-mass star". Nature 462 (17 December 2009): 891–894. Bibcode 2009Natur.462..891C. doi:10.1038/nature08679. PMID 20016595. http://arxiv1.library.cornell.edu/abs/0912.3229. Retrieved 2009-12-15. 
  3. ^ Rojas-Ayala, Barbara; Covey, Kevin R.; Muirhead, Philip S.; Lloyd, James P. (26 July 2010). "Metal-Rich M-dwarf Planet Hosts: Metallicities with K-Band Spectra". e-Print. arXiv:1007.4593v1. Bibcode 2010arXiv1007.4593R. http://arxiv.org/PS_cache/arxiv/pdf/1007/1007.4593v1.pdf. 
  4. ^ a b c d David A. Aguilar (2009-12-16). "Astronomers Find Super-Earth Using Amateur, Off-the-Shelf Technology". Harvard-Smithsonian Center for Astrophysics. http://www.cfa.harvard.edu/news/2009/pr200924.html. Retrieved December 16, 2009. 

See also

External links

Coordinates: 17h 15m 18.94s, +4° 57′ 49.7″

GJ 1214 system
Stars
GJ 1214
Planets