Astronomy:GJ 1214

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Short description: Star in the constellation Ophiuchus
GJ 1214 / Orkaria
GJ1214b (Artist’s impression).jpg
This artist's impression shows how the super-Earth orbiting the nearby star GJ 1214 may look.
Credit: ESO/L. Calçada
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ophiuchus[1]
Right ascension  17h 15m 18.93399s[2]
Declination +04° 57′ 50.0666″[2]
Apparent magnitude (V) 14.71±0.03[3]
Characteristics
Spectral type M4.5[4]
Apparent magnitude (B) 16.40[5]
Apparent magnitude (R) 14.394 ± 0.17[5]
Apparent magnitude (I) 11.52 ± 0.03[3]
Apparent magnitude (J) 9.750±0.024[6]
Apparent magnitude (H) 9.094±0.024[6]
Apparent magnitude (K) 8.782±0.020[6]
B−V color index 1.73[7]
V−R color index 0.9
R−I color index 2.7
Variable type planetary transit[8]
Astrometry
Radial velocity (Rv)+20.91±0.65[2] km/s
Proper motion (μ) RA: 580.202[2] mas/yr
Dec.: −749.713[2] mas/yr
Parallax (π)68.2986 ± 0.0652[2] mas
Distance47.75 ± 0.05 ly
(14.64 ± 0.01 pc)
Absolute magnitude (MV)14.10
Details
Mass0.181±0.005[9] M☉
Radius0.204±0.0085[9] R☉
Luminosity0.00351±0.00010[9] L☉
Surface gravity (log g)4.991±0.029[8] cgs
Temperature3,111+69
−66[9] K
Metallicity [Fe/H]0.11±0.09[9] dex
Rotation125±5 d[10]
Age5–10[11] Gyr
Other designations
Orkaria, GJ 1214, G 139-21, LHS 3275, LSPM J1715+0457, NLTT 44431, 2MASS J17151894+0457496[5]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

GJ 1214 (sometimes Gliese 1214) is a dim M4.5[4] red dwarf star in the constellation Ophiuchus with an apparent magnitude of 14.7.[3] It is located at a distance of 47.8 light-years (14.7 parsecs) from Earth.[12] GJ 1214 hosts one known exoplanet.[8]

Nomenclature

The designation GJ 1214 comes from the Gliese Catalogue of Nearby Stars. This star was first included in the second edition of the catalogue, published in 1979 by Gliese and Jahreiß, hence the GJ prefix usually used for this star.[13]

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project.[14] The approved names, proposed by a team from Kenya, were announced in June 2023. GJ 1214 is named Orkaria and its planet is named Enaiposha, after the Maa words for red ochre and for a large body of water, alluding to the color of the star and likely composition of the planet.[15]

Properties

GJ 1214 is about one-fifth the radius of the Sun[16] with a surface temperature estimated to be 3,110 K (2,840 °C; 5,140 °F).[9] Its luminosity is only 0.35% that of the Sun.[9]

The estimate for the stellar radius is 15% larger than predicted by theoretical models.[8] It also shows a 1% intrinsic variability in the near-infrared probably caused by stellar spots.[3] The star is rotating slowly, with a period that is most likely an integer multiple of 53 days. It is probably at least three billion years old and a member of the old thin disk of the Milky Way.[3] Although GJ 1214 has a low to moderate level of magnetic activity, it does undergo flares and is a source of X-ray emission with a base luminosity of 7.4×1025 erg s−1. The temperature of the stellar corona is estimated to be about 3.5×106 K.[11]

In 2021–2022, the star is suspected to be in the low-activity phase of its magnetic starspot cycle.[17]

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,[8][16] though now more often described as a mini-Neptune based on its composition.[18]

Discovered by the MEarth Project and investigated further by the HARPS spectrograph on ESO’s 3.6-metre telescope at La Silla, GJ 1214 b was the second super-Earth exoplanet for which astronomers determined the mass and radius, giving vital clues about its structure. It was also the first super-Earth around which an atmosphere was found. A search for additional planets using transit timing variations was negative.[3]

No transit-time variations have yet been found for this transit. As of 2012, "the given data does not allow us to conclude that there is a [second] planet in the mass range 0.1–5 Earth-masses and the period range 0.76–1.23 or 1.91–3.18 days."[19] The X-ray flux from the host star is estimated to have stripped 2–5.6 M⊕ from the planet over the lifetime of the system.[11]

The GJ 1214 planetary system[20]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b / Enaiposha 8.17±0.43 M⊕ 0.01490±0.00026 1.580404571(42)[21] <0.063 88.7±0.1° 2.742+0.050
−0.053 R⊕

See also

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific 99 (617): 695–699. doi:10.1086/132034. Bibcode: 1987PASP...99..695R.  Vizier query form
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Berta, Zachory K. et al. (2011). "The GJ1214 Super-Earth System: Stellar Variability, New Transits, and a Search for Additional Planets". The Astrophysical Journal 736 (1): 12. doi:10.1088/0004-637X/736/1/12. Bibcode: 2011ApJ...736...12B. 
  4. ↑ 4.0 4.1 Rojas-Ayala, Bárbara et al. (2010). "Metal-rich M-Dwarf Planet Hosts: Metallicities with K-band Spectra". The Astrophysical Journal Letters 720 (1): L113–L118. doi:10.1088/2041-8205/720/1/L113. Bibcode: 2010ApJ...720L.113R. 
  5. ↑ 5.0 5.1 5.2 "GJ 1214". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GJ+1214. 
  6. ↑ 6.0 6.1 6.2 Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W. et al. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal 131 (2): 1163–1183. doi:10.1086/498708. ISSN 0004-6256. Bibcode: 2006AJ....131.1163S.  Vizier catalog entry
  7. ↑ van Altena, William F. et al.. The General Catalogue of Trigonometric Stellar Parallaxes. Yale University Observatory. Vizier catalog entry
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Charbonneau, David et al. (2009). "A super-Earth transiting a nearby low-mass star". Nature 462 (7275): 891–894. doi:10.1038/nature08679. PMID 20016595. Bibcode: 2009Natur.462..891C. https://wwelsh.sdsu.edu/~wwelsh/CLASSES/ASTR510/PAPERS/GJ1214_Charbonneau.pdf. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal 918 (1): 23. doi:10.3847/1538-4357/ac0aea. 40. Bibcode: 2021ApJ...918...40P. 
  10. ↑ Mallonn, M. et al. (2018). "GJ 1214: Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum". Astronomy and Astrophysics 614: A35. doi:10.1051/0004-6361/201732300. Bibcode: 2018A&A...614A..35M. 
  11. ↑ 11.0 11.1 11.2 Lalitha, S. et al. (July 2014). "X-Ray Emission from the Super-Earth Host GJ 1214". The Astrophysical Journal Letters 790 (1): 5. doi:10.1088/2041-8205/790/1/L11. L11. Bibcode: 2014ApJ...790L..11L. 
  12. ↑ Anglada-Escudé, Guillem; Rojas-Ayala, Bárbara; Boss, Alan P.; Weinberger, Alycia J.; Lloyd, James P. (2012). "GJ 1214b revised. Improved trigonometric parallax, stellar parameters, orbital solution, and bulk properties for the super-Earth GJ 1214b". Astronomy & Astrophysics 551: A48. doi:10.1051/0004-6361/201219250. Bibcode: 2013A&A...551A..48A. 
  13. ↑ "Dictionary of Nomenclature of Celestial Objects". Centre de données astronomiques de Strasbourg. https://cdsweb.u-strasbg.fr/cgi-bin/Dic-Simbad?GJ. 
  14. ↑ "List of ExoWorlds 2022". IAU. 8 August 2022. https://www.nameexoworlds.iau.org/2022exoworlds. 
  15. ↑ "2022 Approved Names". IAU. https://www.nameexoworlds.iau.org/2022approved-names. 
  16. ↑ 16.0 16.1 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. 
  17. ↑ Henry, Gregory W.; Bean, Jacob L. (2023), C14 Automatic Imaging Telescope Photometry of GJ 1214 
  18. ↑ Brennan, Pat (10 May 2023). "NASA's Webb Takes Closest Look Yet at Mysterious Planet". NASA. https://www.jpl.nasa.gov/news/nasas-webb-takes-closest-look-yet-at-mysterious-planet. 
  19. ↑ Kennet B. W. Harpsøe (2012). "The transiting system GJ1214: high-precision defocused transit observations and a search for evidence of transit timing variation". Astronomy & Astrophysics 549: A10. doi:10.1051/0004-6361/201219996. Bibcode: 2013A&A...549A..10H. 
  20. ↑ Cloutier, Ryan; Charbonneau, David; Deming, Drake; Bonfils, Xavier; Astudillo-Defru, Nicola (2021), "A More Precise Mass for GJ 1214 b and the Frequency of Multiplanet Systems Around Mid-M Dwarfs", The Astronomical Journal 162 (5): 174, doi:10.3847/1538-3881/ac1584, Bibcode: 2021AJ....162..174C 
  21. ↑ Kokori, A. et al. (14 February 2023). "ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations". The Astrophysical Journal Supplement Series 265 (1). doi:10.3847/1538-4365/ac9da4. Bibcode: 2023ApJS..265....4K.  Vizier catalog entry

External links

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



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