Afficher la notice abrégée

Strong biases in retrieved atmospheric composition caused by day–night chemical heterogeneities

hal.structure.identifierECLIPSE 2020
dc.contributor.authorPLURIEL, William
hal.structure.identifierECLIPSE 2020
dc.contributor.authorZINGALES, Tiziano
hal.structure.identifierECLIPSE 2020
dc.contributor.authorLECONTE, Jérémy
dc.contributor.authorPARMENTIER, Vivien
dc.date.issued2020
dc.identifier.issn0004-6361
dc.description.abstractEnMost planets currently amenable to transit spectroscopy are close enough to their host stars to exhibit a relatively strong day to night temperature gradient. For hot planets this leads to a chemical composition dichotomy between the two hemispheres. In the extreme case of ultra-hot Jupiters, some species, such as molecular hydrogen and water, are strongly dissociated on the day side while others, such as carbon monoxide, are not. However, most current retrieval algorithms rely on 1D forward models that are unable to reproduce this effect. We thus investigate how the 3D structure of the atmosphere biases the abundances retrieved using commonly used algorithms. We study the case of Wasp-121b as a prototypical ultra-hot Jupiter. We use the simulations of this planet performed with the Substellar and Planetary Atmospheric Radiation and Circulation global climate model and generate transmission spectra that fully account for the 3D structure of the atmosphere with Pytmosph3R. These spectra are then analyzed using the TauREx retrieval code. We find that the ultra-hot Jupiter transmission spectra exhibit muted H2O features that originate on the night side where the temperature, hence the scale-height, is smaller than on the day side. However, the spectral features of molecules present on the day side are boosted by both its high temperature and low mean molecular weight. As a result, the retrieved parameters are strongly biased compared to the ground truth. In particular the [CO]/[H2O] is overestimated by one to three orders of magnitude. This must be kept in mind when using the retrieval analysis to infer the C/O of a planet’s atmosphere. We also discuss whether indicators can allow us to infer the 3D structure of an observed atmosphere. Finally, we show that Wide Field Camera 3 from Hubble Space Telescope transmission data of Wasp-121b are compatible with the day–night thermal and compositional dichotomy predicted by models.
dc.language.isoen
dc.publisherEDP Sciences
dc.rights.urihttp://creativecommons.org/licenses/by/
dc.subject.enplanets and satellites: atmospheres
dc.subject.enradiative transfer
dc.subject.entechniques: spectroscopic
dc.subject.enmethods: numerical
dc.title.enStrong biases in retrieved atmospheric composition caused by day–night chemical heterogeneities
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/202037678
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA66
bordeaux.volume636
bordeaux.peerReviewedoui
hal.identifierhal-02903831
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02903831v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2020&rft.volume=636&rft.spage=A66&rft.epage=A66&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=PLURIEL,%20William&ZINGALES,%20Tiziano&LECONTE,%20J%C3%A9r%C3%A9my&PARMENTIER,%20Vivien&rft.genre=article


Fichier(s) constituant ce document

FichiersTailleFormatVue

Il n'y a pas de fichiers associés à ce document.

Ce document figure dans la(les) collection(s) suivante(s)

Afficher la notice abrégée