Chthon (from Greek: Χθών) means "earth". The term chthonian was coined by Hébrard, et al., and generally refers to Greek chthonic deities from the infernal underground.
Possible examples
Transit-timing variation measurements indicate, for example, that Kepler-52b, Kepler-52c and Kepler-57b have maximum masses between 30 and 100 times the mass of Earth (although the actual masses could be much lower); with radii about two Earth radii,[2] they might have densities larger than that of an iron planet of the same size. These exoplanets are orbiting very close to their stars and could be the remnant cores of evaporated gas giants or brown dwarfs. If cores are massive enough they could remain compressed for billions of years despite losing the atmospheric mass.[3][4]
As there is a lack of gaseous "hot-super-Earths" between 2.2 and 3.8 Earth-radii exposed to over 650 Earth incident flux, it is assumed that exoplanets below such radii exposed to such stellar fluxes could have had their envelopes stripped by photoevaporation.[5]
HD 209458 b is an example of a gas giant that is in the process of having its atmosphere stripped away, though it will not become a chthonian planet for many billions of years, if ever. A similar case would be Gliese 436b, which has already lost 10% of its atmosphere.[6]
CoRoT-7b is the first exoplanet found that might be chthonian.[7][8] Other researchers dispute this, and conclude COROT-7b was always a rocky planet and not the eroded core of a gas or ice giant,[9] due to the young age of the star system.
In 2020, a high-density planet more massive than Neptune was found very close to its host star, within the Neptunian Desert. This world, TOI 849 b, may very well be a chthonian planet.[10]
^Hébrard G., Lecavelier Des Étangs A., Vidal-Madjar A., Désert J.-M., Ferlet R. (2003), Evaporation Rate of Hot Jupiters and Formation of chthonian Planets, Extrasolar Planets: Today and Tomorrow, ASP Conference Proceedings, Vol. 321, held 30 June – 4 July 2003, Institut d'astrophysique de Paris, France. Edited by Jean-Philippe Beaulieu, Alain Lecavelier des Étangs and Caroline Terquem.
^Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability, Jason H. Steffen et al, 16 Aug 2012
^Mocquet, A.; Grasset, O. and Sotin, C. (2013) Super-dense remnants of gas giant exoplanets, EPSC Abstracts, Vol. 8, EPSC2013-986-1, European Planetary Science Congress 2013
^Mocquet, A.; Grasset, O.; Sotin, C. (2014). "Very high-density planets: a possible remnant of gas giants". Phil. Trans. R. Soc. A. 372 (2014): 20130164. Bibcode:2014RSPTA.37230164M. doi:10.1098/rsta.2013.0164. PMID 24664925.
^Lundkvist et al. (2016), Hot super-Earths stripped by their host stars, arXiv:1604.05220 [astro-ph.EP]
^"Hubble sees atmosphere being stripped from Neptune-sized exoplanet". Nature. 2015-06-24. Retrieved 2015-11-08.
^. Astrobiology Magazine. 2009-04-25. Archived from the original on 2018-01-07. Retrieved 2018-01-07.{{cite web}}: CS1 maint: unfit URL (link)
^ "Super-Earth 'began as gas giant'". BBC News. 10 January 2010. Retrieved 2010-01-10.
^ Odert, P. (2010). "Thermal mass-loss of exoplanets in close orbits" (PDF). EPSC Abstracts. 5: 582. Bibcode:2010epsc.conf..582O.
^Armstrong DJ, Lopez TA, Zhan Z (June 1, 2020). "A remnant planetary core in the hot-Neptune desert". Nature. 583 (7814): 39–42. arXiv:2003.10314. Bibcode:2020Natur.583...39A. doi:10.1038/s41586-020-2421-7. PMID 32612222. S2CID 214612138.
March 25, 2023
chthonian, planet, sometimes, cthonian, hypothetical, class, celestial, objects, resulting, from, stripping, away, giant, hydrogen, helium, atmosphere, outer, layers, which, called, hydrodynamic, escape, such, atmospheric, stripping, likely, result, proximity,. Chthonian planets ˈ k 8 oʊ n i e n sometimes cthonian are a hypothetical class of celestial objects resulting from the stripping away of a gas giant s hydrogen and helium atmosphere and outer layers which is called hydrodynamic escape Such atmospheric stripping is a likely result of proximity to a star The remaining rocky or metallic core would resemble a terrestrial planet in many respects 1 Artist s conception of COROT 7b Artist s conception of HD 209458 b transiting its star Contents 1 Etymology 2 Possible examples 3 See also 4 ReferencesEtymology EditChthon from Greek X8wn means earth The term chthonian was coined by Hebrard et al and generally refers to Greek chthonic deities from the infernal underground Possible examples EditTransit timing variation measurements indicate for example that Kepler 52b Kepler 52c and Kepler 57b have maximum masses between 30 and 100 times the mass of Earth although the actual masses could be much lower with radii about two Earth radii 2 they might have densities larger than that of an iron planet of the same size These exoplanets are orbiting very close to their stars and could be the remnant cores of evaporated gas giants or brown dwarfs If cores are massive enough they could remain compressed for billions of years despite losing the atmospheric mass 3 4 As there is a lack of gaseous hot super Earths between 2 2 and 3 8 Earth radii exposed to over 650 Earth incident flux it is assumed that exoplanets below such radii exposed to such stellar fluxes could have had their envelopes stripped by photoevaporation 5 HD 209458 b is an example of a gas giant that is in the process of having its atmosphere stripped away though it will not become a chthonian planet for many billions of years if ever A similar case would be Gliese 436b which has already lost 10 of its atmosphere 6 CoRoT 7b is the first exoplanet found that might be chthonian 7 8 Other researchers dispute this and conclude COROT 7b was always a rocky planet and not the eroded core of a gas or ice giant 9 due to the young age of the star system In 2020 a high density planet more massive than Neptune was found very close to its host star within the Neptunian Desert This world TOI 849 b may very well be a chthonian planet 10 See also EditCOROT 7b Hot Jupiter Pulsar planet Hypothetical astronomical object Kepler 70 Mini Neptune Super Earth KELT 9bReferences Edit Hebrard G Lecavelier Des Etangs A Vidal Madjar A Desert J M Ferlet R 2003 Evaporation Rate of Hot Jupiters and Formation of chthonian Planets Extrasolar Planets Today and Tomorrow ASP Conference Proceedings Vol 321 held 30 June 4 July 2003 Institut d astrophysique de Paris France Edited by Jean Philippe Beaulieu Alain Lecavelier des Etangs and Caroline Terquem Transit Timing Observations from Kepler VII Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability Jason H Steffen et al 16 Aug 2012 Mocquet A Grasset O and Sotin C 2013 Super dense remnants of gas giant exoplanets EPSC Abstracts Vol 8 EPSC2013 986 1 European Planetary Science Congress 2013 Mocquet A Grasset O Sotin C 2014 Very high density planets a possible remnant of gas giants Phil Trans R Soc A 372 2014 20130164 Bibcode 2014RSPTA 37230164M doi 10 1098 rsta 2013 0164 PMID 24664925 Lundkvist et al 2016 Hot super Earths stripped by their host stars arXiv 1604 05220 astro ph EP Hubble sees atmosphere being stripped from Neptune sized exoplanet Nature 2015 06 24 Retrieved 2015 11 08 Exoplanets Exposed to the Core Astrobiology Magazine 2009 04 25 Archived from the original on 2018 01 07 Retrieved 2018 01 07 a href Template Cite web html title Template Cite web cite web a CS1 maint unfit URL link Super Earth began as gas giant BBC News 10 January 2010 Retrieved 2010 01 10 Odert P 2010 Thermal mass loss of exoplanets in close orbits PDF EPSC Abstracts 5 582 Bibcode 2010epsc conf 582O Armstrong DJ Lopez TA Zhan Z June 1 2020 A remnant planetary core in the hot Neptune desert Nature 583 7814 39 42 arXiv 2003 10314 Bibcode 2020Natur 583 39A doi 10 1038 s41586 020 2421 7 PMID 32612222 S2CID 214612138 Retrieved from https en wikipedia org w index php title Chthonian planet amp oldid 1145732077, wikipedia, wiki, book, books, library,
