Gliese 1214 b[4] (often shortened to GJ 1214 b) is an exoplanet that orbits the star Gliese 1214, and was discovered in December 2009. Its parent star is 48 light-years from the Sun, in the constellation Ophiuchus. As of 2017, GJ 1214 b is the most likely known candidate for being an ocean planet.[5][6] For that reason, scientists have nicknamed the planet "the waterworld".[7]
GJ 1214 b
Size comparison of GJ 1214 b with Earth (left) and Neptune (right). The actual color of GJ 1214 b is not yet known.
It is a super-Earth, meaning it is larger than Earth but is significantly smaller (in mass and radius) than the gas giants of the Solar System. After CoRoT-7b, it was the second super-Earth to have both its mass and radius measured[1] and is the first of a new class of planets with small size and relatively low density.[8] GJ 1214 b is also significant because its parent star is relatively near the Sun and because it transits (crosses in front of) that parent star, which allows the planet's atmosphere to be studied using spectroscopic methods.[1]
GJ 1214 b was first detected by the MEarth Project, which searches for the small drops in brightness that can occur when an orbiting planet briefly passes in front of its parent star. In early 2009, the astronomers running the project noticed that the star GJ 1214 appeared to show drops in brightness of that sort. They then observed the star more closely and confirmed that it dimmed by roughly 1.5% every 1.58 days. Follow-up radial-velocity measurements were then made with the HARPS spectrograph on the ESO's 3.6-meter telescope at La Silla, Chile; those measurements succeeded in providing independent evidence for the reality of the planet. A paper was then published in Nature announcing the planet and giving estimates of its mass, radius, and orbital parameters.[1]
Features
Artist's impression of the planet with a possible deep ocean
Artist's impression of Gliese 1214 b (foreground), illuminated by the red light of its parent star (center)'
This artist's impression shows how GJ 1214 b may look as it transits its parent star. It is the second super-Earth for which astronomers have determined the mass and radius, giving vital clues about its structure.
The radius of GJ 1214 b can be inferred from the amount of dimming seen when the planet crosses in front of its parent star as viewed from Earth. The mass of the planet can be inferred from sensitive observations of the parent star's radial velocity, measured through small shifts in stellar spectral lines due to the Doppler effect.[1] Given the planet's mass and radius, its density can be calculated. Through a comparison with theoretical models, the density in turn provides limited but highly useful information about the composition and structure of the planet.[1]
Due to the relatively small size of GJ 1214 b's parent star, it is feasible to perform spectroscopic observations during planetary transits. By comparing the observed spectrum before and during transits, the spectrum of the planetary atmosphere can be inferred. In December 2010, a study was published showing the spectrum to be largely featureless over the wavelength range of 750–1000 nm. Because a thick and cloud-free hydrogen-rich atmosphere would have produced detectable spectral features, such an atmosphere appears to be ruled out. Although no clear signs were observed of water vapor or any other molecule, the authors of the study believe the planet may have an atmosphere composed mainly of water vapor. Another possibility is that there may be a thick layer of high clouds, which absorbs the starlight.[14] Because of the estimated old age of the planetary system and the calculated hydrodynamic escape (loss of gasses that tends to deplete an atmosphere of higher molecular-weight constituents) rate of 900 tonnes per second, scientists conclude that there has been a significant atmospheric loss during the lifetime of the planet and any current atmosphere cannot be primordial.[1] The loss of primordial atmosphere was indirectly confirmed in 2020 as no helium was detected at Gliese 1214 b.[15] Helium was detected in the atmosphere of Gliese 1214 b by 2022 though.[16]
While very little is known about GJ 1214 b, there has been speculation as to its specific nature and composition. On the basis of planetary models[18] it has been suggested that GJ 1214 b has a relatively thick gaseous envelope,[8] totaling about 5% of planetary mass.[3] It is possible to propose structures by assuming different compositions, guided by scenarios for the formation and evolution of the planet.[8] GJ 1214 b could be a rocky planet with an outgassed hydrogen-rich atmosphere, a mini-Neptune, or an ocean planet.[8] If it is a waterworld, it could possibly be thought of as a bigger and hotter version of Jupiter's Galilean moonEuropa.[8] While no scientist has stated to believe GJ 1214 b is an ocean planet, if GJ 1214 b is assumed to be an ocean planet,[18] i.e. the interior is assumed to be composed primarily of a water core surrounded by more water, proportions of the total mass consistent with the mass and radius are about 25% rock and 75% water, covered by a thick envelope of gases such as hydrogen and helium (c. 0.05%).[1][17] Water planets could result from inward planetary migration and originate as protoplanets that formed from volatile ice-rich material beyond the snow-line but that never attained masses sufficient to accrete large amounts of H/He nebular gas.[8] Because of the varying pressure at depth, models of a water world include "steam, liquid, superfluid, high-pressure ices, and plasma phases" of water.[8] Some of the solid-phase water could be in the form of ice VII.[17]
^ abcdefghijCharbonneau, David; et al. (2009). "A super-Earth transiting a nearby low-mass star". Nature. 462 (7275): 891–894. arXiv:0912.3229. Bibcode:2009Natur.462..891C. doi:10.1038/nature08679. PMID 20016595.
^Kennet B. W. Harpsøe; et al. (2012). "The Transiting System GJ1214". Astronomy & Astrophysics. 549: A10. arXiv:1207.3064. Bibcode:2013A&A...549A..10H. doi:10.1051/0004-6361/201219996.
^ abcA More Precise Mass for GJ 1214 b and the Frequency of Multi-Planet Systems Around Mid-M Dwarfs, 2021, arXiv:2107.14732
^Rein, Hanno; et al. "Open Exoplanet Catalogue – Gliese 1214 b". Open Exoplanet Catalogue. Retrieved 2 January 2014.
^David Charbonneau; Zachory K. Berta; Jonathan Irwin; Christopher J. Burke; et al. (2009). "A super-Earth transiting a nearby low-mass star". Nature. 462 (17 December 2009): 891–894. arXiv:0912.3229. Bibcode:2009Natur.462..891C. doi:10.1038/nature08679. PMID 20016595.
^Kuchner, Seager; Hier-Majumder, M.; Militzer, C. A. (2007). "Mass–radius relationships for solid exoplanets". The Astrophysical Journal. 669 (2): 1279–1297. arXiv:0707.2895. Bibcode:2007ApJ...669.1279S. doi:10.1086/521346.
^"10 Real Planets That Are Stranger Than Science Fiction". Retrieved 2015-06-13.
^ abcdefgRogers, L.A.; Seager, S. (2010). "Three Possible Origins for the Gas Layer on GJ 1214b". The Astrophysical Journal (abstract). 716 (2): 1208–1216. arXiv:0912.3243. Bibcode:2010ApJ...716.1208R. doi:10.1088/0004-637X/716/2/1208.
^Harrington, J.D.; Weaver, Donna; Villard, Ray (December 31, 2013). "Release 13-383 – NASA's Hubble Sees Cloudy Super-Worlds With Chance for More Clouds". NASA. Retrieved January 1, 2014.
^Moses, Julianne (January 1, 2014). "Extrasolar planets: Cloudy with a chance of dustballs". Nature. 505 (7481): 31–32. Bibcode:2014Natur.505...31M. doi:10.1038/505031a. PMID 24380949.
^Knutson, Heather; et al. (January 1, 2014). "A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b". Nature. 505 (7481): 66–68. arXiv:1401.3350. Bibcode:2014Natur.505...66K. doi:10.1038/nature12887. PMID 24380953.
^Kreidberg, Laura; et al. (January 1, 2014). "Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b". Nature. 505 (7481): 69–72. arXiv:1401.0022. Bibcode:2014Natur.505...69K. doi:10.1038/nature12888. PMID 24380954.
^"List of ExoWorlds 2022". nameexoworlds.iau.org. IAU. 8 August 2022. Retrieved 27 August 2022.
^Bean, Jacob L.; Kempton, Eliza Miller-Ricci; Homeier, Derek (2010). "A ground-based transmission spectrum of the super-Earth exoplanet GJ 1214b". Nature. 468 (7324): 669–672. arXiv:1012.0331. Bibcode:2010Natur.468..669B. doi:10.1038/nature09596. PMID 21124452.
^Non-detection of Helium in the Upper Atmospheres of Three Sub-Neptune Exoplanets, 2020, arXiv:2007.12968
^A tentative detection of He i in the atmosphere of GJ 1214 b, 2022, arXiv:2201.11120
^ abcDavid A. Aguilar (2009-12-16). "Astronomers Find Super-Earth Using Amateur, Off-the-Shelf Technology". Harvard-Smithsonian Center for Astrophysics. Retrieved December 16, 2009.
^ abSeager, S.; Kuchner, M.; Hier-Majumder, C. A.; Militzer, B. (2007). "Mass–radius relationships for solid exoplanets". The Astrophysical Journal. 669 (2): 1279–1297. arXiv:0707.2895. Bibcode:2007ApJ...669.1279S. doi:10.1086/521346.
External links
Media related to GJ 1214 b at Wikimedia Commons
Astronomers Find World with Thick, Inhospitable Atmosphere and an Icy Heart
Hubble reveals a new class of planet
Astronomers have claimed the existence of a new class of planet: a "water-world" with a thick, steamy atmosphere.
gliese, 1214, often, shortened, 1214, exoplanet, that, orbits, star, gliese, 1214, discovered, december, 2009, parent, star, light, years, from, constellation, ophiuchus, 2017, 1214, most, likely, known, candidate, being, ocean, planet, that, reason, scientist. Gliese 1214 b 4 often shortened to GJ 1214 b is an exoplanet that orbits the star Gliese 1214 and was discovered in December 2009 Its parent star is 48 light years from the Sun in the constellation Ophiuchus As of 2017 GJ 1214 b is the most likely known candidate for being an ocean planet 5 6 For that reason scientists have nicknamed the planet the waterworld 7 GJ 1214 bSize comparison of GJ 1214 b with Earth left and Neptune right The actual color of GJ 1214 b is not yet known DiscoveryDiscovered byDavid Charbonneau et al 1 Discovery siteFred Lawrence Whipple ObservatoryDiscovery dateDecember 16 2009Detection methodTransit MEarth Project Orbital characteristicsSemi major axis0 0143 0 0019 AUEccentricity lt 0 27Orbital period sidereal 1 580404 56 0 000000 16 2 dInclination88 62 0 36 0 28StarGJ 1214Physical characteristicsMean radius2 742 0 050 0 053 3 REarthMass8 17 0 43 3 MEarthMean density1870 400 kg m 3Surface gravity0 91 gTemperature393 555 K 120 282 C 248 539 F equilibrium 1 It is a super Earth meaning it is larger than Earth but is significantly smaller in mass and radius than the gas giants of the Solar System After CoRoT 7b it was the second super Earth to have both its mass and radius measured 1 and is the first of a new class of planets with small size and relatively low density 8 GJ 1214 b is also significant because its parent star is relatively near the Sun and because it transits crosses in front of that parent star which allows the planet s atmosphere to be studied using spectroscopic methods 1 In December 2013 NASA reported that clouds may have been detected in the atmosphere of GJ 1214 b 9 10 11 12 In August 2022 this planet and its host star were included among 20 systems to be named by the third NameExoWorlds project 13 Contents 1 Detection 2 Features 2 1 Speculation based on planetary models 3 See also 4 References 5 External linksDetection EditGJ 1214 b was first detected by the MEarth Project which searches for the small drops in brightness that can occur when an orbiting planet briefly passes in front of its parent star In early 2009 the astronomers running the project noticed that the star GJ 1214 appeared to show drops in brightness of that sort They then observed the star more closely and confirmed that it dimmed by roughly 1 5 every 1 58 days Follow up radial velocity measurements were then made with the HARPS spectrograph on the ESO s 3 6 meter telescope at La Silla Chile those measurements succeeded in providing independent evidence for the reality of the planet A paper was then published in Nature announcing the planet and giving estimates of its mass radius and orbital parameters 1 Features Edit Artist s impression of the planet with a possible deep ocean Artist s impression of Gliese 1214 b foreground illuminated by the red light of its parent star center This artist s impression shows how GJ 1214 b may look as it transits its parent star It is the second super Earth for which astronomers have determined the mass and radius giving vital clues about its structure The radius of GJ 1214 b can be inferred from the amount of dimming seen when the planet crosses in front of its parent star as viewed from Earth The mass of the planet can be inferred from sensitive observations of the parent star s radial velocity measured through small shifts in stellar spectral lines due to the Doppler effect 1 Given the planet s mass and radius its density can be calculated Through a comparison with theoretical models the density in turn provides limited but highly useful information about the composition and structure of the planet 1 Due to the relatively small size of GJ 1214 b s parent star it is feasible to perform spectroscopic observations during planetary transits By comparing the observed spectrum before and during transits the spectrum of the planetary atmosphere can be inferred In December 2010 a study was published showing the spectrum to be largely featureless over the wavelength range of 750 1000 nm Because a thick and cloud free hydrogen rich atmosphere would have produced detectable spectral features such an atmosphere appears to be ruled out Although no clear signs were observed of water vapor or any other molecule the authors of the study believe the planet may have an atmosphere composed mainly of water vapor Another possibility is that there may be a thick layer of high clouds which absorbs the starlight 14 Because of the estimated old age of the planetary system and the calculated hydrodynamic escape loss of gasses that tends to deplete an atmosphere of higher molecular weight constituents rate of 900 tonnes per second scientists conclude that there has been a significant atmospheric loss during the lifetime of the planet and any current atmosphere cannot be primordial 1 The loss of primordial atmosphere was indirectly confirmed in 2020 as no helium was detected at Gliese 1214 b 15 Helium was detected in the atmosphere of Gliese 1214 b by 2022 though 16 GJ 1214 b may be cooler than any other known transiting planet prior to the discovery of Kepler 16b in 2011 by the Kepler mission Its equilibrium temperature is believed to be in the range of 393 555 K 120 282 C 248 539 F depending on how much of the star s radiation is reflected into space 1 17 Speculation based on planetary models Edit While very little is known about GJ 1214 b there has been speculation as to its specific nature and composition On the basis of planetary models 18 it has been suggested that GJ 1214 b has a relatively thick gaseous envelope 8 totaling about 5 of planetary mass 3 It is possible to propose structures by assuming different compositions guided by scenarios for the formation and evolution of the planet 8 GJ 1214 b could be a rocky planet with an outgassed hydrogen rich atmosphere a mini Neptune or an ocean planet 8 If it is a waterworld it could possibly be thought of as a bigger and hotter version of Jupiter s Galilean moon Europa 8 While no scientist has stated to believe GJ 1214 b is an ocean planet if GJ 1214 b is assumed to be an ocean planet 18 i e the interior is assumed to be composed primarily of a water core surrounded by more water proportions of the total mass consistent with the mass and radius are about 25 rock and 75 water covered by a thick envelope of gases such as hydrogen and helium c 0 05 1 17 Water planets could result from inward planetary migration and originate as protoplanets that formed from volatile ice rich material beyond the snow line but that never attained masses sufficient to accrete large amounts of H He nebular gas 8 Because of the varying pressure at depth models of a water world include steam liquid superfluid high pressure ices and plasma phases of water 8 Some of the solid phase water could be in the form of ice VII 17 See also EditCOROT 7b Gliese 581 c Gliese 581 d Gliese 876 d HD 149026 b Lists of astronomical objects MOA 2007 BLG 192LbReferences Edit a b c d e f g h i j Charbonneau David et al 2009 A super Earth transiting a nearby low mass star Nature 462 7275 891 894 arXiv 0912 3229 Bibcode 2009Natur 462 891C doi 10 1038 nature08679 PMID 20016595 Kennet B W Harpsoe et al 2012 The Transiting System GJ1214 Astronomy amp Astrophysics 549 A10 arXiv 1207 3064 Bibcode 2013A amp A 549A 10H doi 10 1051 0004 6361 201219996 a b c A More Precise Mass for GJ 1214 b and the Frequency of Multi Planet Systems Around Mid M Dwarfs 2021 arXiv 2107 14732 Rein Hanno et al Open Exoplanet Catalogue Gliese 1214 b Open Exoplanet Catalogue Retrieved 2 January 2014 David Charbonneau Zachory K Berta Jonathan Irwin Christopher J Burke et al 2009 A super Earth transiting a nearby low mass star Nature 462 17 December 2009 891 894 arXiv 0912 3229 Bibcode 2009Natur 462 891C doi 10 1038 nature08679 PMID 20016595 Kuchner Seager Hier Majumder M Militzer C A 2007 Mass radius relationships for solid exoplanets The Astrophysical Journal 669 2 1279 1297 arXiv 0707 2895 Bibcode 2007ApJ 669 1279S doi 10 1086 521346 10 Real Planets That Are Stranger Than Science Fiction Retrieved 2015 06 13 a b c d e f g Rogers L A Seager S 2010 Three Possible Origins for the Gas Layer on GJ 1214b The Astrophysical Journal abstract 716 2 1208 1216 arXiv 0912 3243 Bibcode 2010ApJ 716 1208R doi 10 1088 0004 637X 716 2 1208 Harrington J D Weaver Donna Villard Ray December 31 2013 Release 13 383 NASA s Hubble Sees Cloudy Super Worlds With Chance for More Clouds NASA Retrieved January 1 2014 Moses Julianne January 1 2014 Extrasolar planets Cloudy with a chance of dustballs Nature 505 7481 31 32 Bibcode 2014Natur 505 31M doi 10 1038 505031a PMID 24380949 Knutson Heather et al January 1 2014 A featureless transmission spectrum for the Neptune mass exoplanet GJ 436b Nature 505 7481 66 68 arXiv 1401 3350 Bibcode 2014Natur 505 66K doi 10 1038 nature12887 PMID 24380953 Kreidberg Laura et al January 1 2014 Clouds in the atmosphere of the super Earth exoplanet GJ 1214b Nature 505 7481 69 72 arXiv 1401 0022 Bibcode 2014Natur 505 69K doi 10 1038 nature12888 PMID 24380954 List of ExoWorlds 2022 nameexoworlds iau org IAU 8 August 2022 Retrieved 27 August 2022 Bean Jacob L Kempton Eliza Miller Ricci Homeier Derek 2010 A ground based transmission spectrum of the super Earth exoplanet GJ 1214b Nature 468 7324 669 672 arXiv 1012 0331 Bibcode 2010Natur 468 669B doi 10 1038 nature09596 PMID 21124452 Non detection of Helium in the Upper Atmospheres of Three Sub Neptune Exoplanets 2020 arXiv 2007 12968 A tentative detection of He i in the atmosphere of GJ 1214 b 2022 arXiv 2201 11120 a b c David A Aguilar 2009 12 16 Astronomers Find Super Earth Using Amateur Off the Shelf Technology Harvard Smithsonian Center for Astrophysics Retrieved December 16 2009 a b Seager S Kuchner M Hier Majumder C A Militzer B 2007 Mass radius relationships for solid exoplanets The Astrophysical Journal 669 2 1279 1297 arXiv 0707 2895 Bibcode 2007ApJ 669 1279S doi 10 1086 521346 External links Edit Media related to GJ 1214 b at Wikimedia Commons Astronomers Find World with Thick Inhospitable Atmosphere and an Icy Heart MEarth Project Hubble reveals a new class of planet Astronomers have claimed the existence of a new class of planet a water world with a thick steamy atmosphere An update on the atmosphere of super Earth GJ1214b Portals Astronomy Stars Outer space Retrieved from https en wikipedia org w index php title Gliese 1214 b amp oldid 1126765573, wikipedia, wiki, book, books, library,
