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Evolution of the solar activity over time and effects on planetary atmospheres. II. kappa^1 Ceti, an analog of the Sun when life arose on Earth

hal.structure.identifierInstitut de Ciencies de l'Espai [Barcelona] [ICE-CSIC]
dc.contributor.authorRIBAS, I.
dc.contributor.authorDE MELLO, G. F. Porto
dc.contributor.authorFERREIRA, L. D.
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
dc.contributor.authorHÉBRARD, Eric
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
dc.contributor.authorSELSIS, Franck
dc.contributor.authorCATALAN, S.
dc.contributor.authorGARCES, A.
dc.contributor.authorNASCIMENTO JR., J. D. Do
hal.structure.identifierGroupe de Recherche en Astronomie et Astrophysique du Languedoc [GRAAL]
hal.structure.identifierDepartamento de Fisica
dc.contributor.authorDE MEDEIROS, J. R.
dc.date.created2010
dc.date.issued2010
dc.identifier.issn0004-637X
dc.description.abstractEnThe early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigation of the atmospheric parameters, state of evolution and high-energy fluxes of the nearby star kap^1 Cet, previously thought to have properties resembling those of the early Sun. Atmospheric parameters were derived from the excitation/ionization equilibrium of Fe I and Fe II, profile fitting of Halpha and the spectral energy distribution. The UV irradiance was derived from FUSE and HST data, and the absolute chromospheric flux from the Halpha line core. From careful spectral analysis and the comparison of different methods we propose for kap^1 Cet the following atmospheric parameters: Teff = 5665+/-30 K (Halpha profile and energy distribution), log g = 4.49+/-0.05 dex (evolutionary and spectroscopic) and [Fe/H] = +0.10+/-0.05 dex (Fe II lines). The UV radiative properties of kap^1 Cet indicate that its flux is some 35% lower than the current Sun's between 210 and 300 nm, it matches the Sun's at 170 nm and increases to at least 2-7 times higher than the Sun's between 110 and 140 nm. The use of several indicators ascribes an age to kap^1 Cet in the interval ~0.4-0.8 Gyr and the analysis of the theoretical HR diagram suggests a mass ~1.04 Msun. This star is thus a very close analog of the Sun when life arose on Earth and Mars is thought to have lost its surface bodies of liquid water. Photochemical models indicate that the enhanced UV emission leads to a significant increase in photodissociation rates compared with those commonly assumed of the early Earth. Our results show that reliable calculations of the chemical composition of early planetary atmospheres need to account for the stronger solar photodissociating UV irradiation.
dc.language.isoen
dc.publisherAmerican Astronomical Society
dc.subject.entechniques: spectroscopic
dc.subject.enplanets and satellites: atmospheres
dc.subject.enstars: abundances
dc.subject.enstars: activity
dc.subject.enstars: late-type
dc.title.enEvolution of the solar activity over time and effects on planetary atmospheres. II. kappa^1 Ceti, an analog of the Sun when life arose on Earth
dc.typeArticle de revue
dc.identifier.doi10.1088/0004-637X/714/1/384
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Astrophysique stellaire et solaire [astro-ph.SR]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique stellaire et solaire [astro-ph.SR]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv1003.3561
bordeaux.journalThe Astrophysical Journal
bordeaux.page384-395
bordeaux.volume714
bordeaux.issue1
bordeaux.peerReviewedoui
hal.identifierhal-00521699
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00521699v1
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