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dc.contributor.authorVENOT, O.
hal.structure.identifierSSE 2014
dc.contributor.authorAGÚNDEZ, M.
hal.structure.identifierSSE 2014
dc.contributor.authorSELSIS, Franck
dc.contributor.authorTESSENYI, Marcell
hal.structure.identifierDept of Physics
dc.contributor.authorIRO, Nicolas
dc.date.created2013-12-18
dc.date.issued2014
dc.identifier.issn0004-6361
dc.description.abstractEnCurrent observation techniques are able to probe the atmosphere of some giant exoplanets and get some clues about their atmospheric composition. However, the chemical compositions derived from observations are not fully understood, as for instance in the case of the CH4/CO abundance ratio, which is often inferred different from what has been predicted by chemical models. Recently, the warm Neptune GJ3470b has been discovered and because of its close distance from us and high transit depth, it is a very promising candidate for follow up characterisation of its atmosphere. We study the atmospheric composition of GJ3470b in order to compare with the current observations of this planet, to prepare the future ones, but also as a typical case study to understand the chemical composition of warm (sub-)Neptunes. The metallicity of such atmospheres is totally uncertain, and vary probably to values up to 100x solar. We explore the space of unknown parameters to predict the range of possible atmospheric compositions. Within the parameter space explored we find that in most cases methane is the major carbon-bearing species. We however find that in some cases, typically for high metallicities with a sufficiently high temperature the CH4/CO abundance ratio can become lower than unity, as suggested by some multiwavelength photometric observations of other warm (sub-)Neptunes, such as GJ1214b and GJ436b. As for the emission spectrum of GJ3470b, brightness temperatures at infrared wavelengths may vary between 400 and 800K depending on the thermal profile and metallicity. Combined with a hot temperature profile, a substantial enrichment in heavy elements by a factor of 100 with respect to the solar composition can shift the carbon balance in favour of carbon monoxide at the expense of CH4. Nevertheless, current observations of this planet do not allow yet to determine which model is more accurate.
dc.language.isoen
dc.publisherEDP Sciences
dc.title.enThe atmospheric chemistry of the warm Neptune GJ 3470b: influence of metallicity and temperature on the CH4/CO ratio
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201322485
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv1312.5163
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageid.A51
bordeaux.volume562
bordeaux.peerReviewedoui
hal.identifierhal-00949332
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00949332v1
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