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The transmission spectrum of Earth-size transiting planets

Ehrenreich, D. and Tinetti, G. and Lecavelier des Etangs, A. and Vidal-Madjar, A. and Selsis, F. (2006) The transmission spectrum of Earth-size transiting planets. Astronomy & Astrophysics, 448 (1). pp. 379-393. ISSN 0004-6361.

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A variety of terrestrial planets with different physical parameters and exotic atmospheres might plausibly exist outside our Solar System, waiting to be detected by the next generation of space-exploration missions. Some of these planets might be transiting their parent star. We present here a detailed study of the atmospheric signatures of transiting Earth-size exoplanets. We focus on a limited number of significant examples, for which we discuss the detectability of some of the possible molecules present in their atmospheres, such as water (H_2O), carbon dioxide (CO_2), ozone (O_3), or molecular oxygen (O_2). To this purpose, we developed a model to simulate transmission spectra of Earth-size exoplanets from the ultraviolet (UV) to the near infrared (NIR). According to our calculations, the signatures of planetary atmospheres represent an absorption of a few parts-per-million (ppm) in the stellar flux. The atmospheres of a few Earth-like planets can be detected with a 30-40 m telescope. The detection of the extensive atmospheres of tens of small satellites of giant exoplanets and hundreds of hypothetical ocean-planets can be achieved with 20-30 m and 10-20 m instruments, respectively, provided all these planets are frequent and they are efficiently surveyed. We also found that planets around K stars are favored, mainly because these stars are more numerous and smaller compared to G or F stars. While not addressed in this study, limitations might come from stellar photometric micro-variability.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ehrenreich, D.0000-0001-9704-5405
Lecavelier des Etangs, A.0000-0002-5637-5253
Selsis, F.0000-0001-9619-5356
Additional Information:© ESO 2006. Received 19 July 2005 / Accepted 29 September 2005. We warmly thank Chris Parkinson for careful reading and comments that noticeably improved the manuscript, David Crisp for the code LBLABC, and the anonymous referee for a thorough reading and useful comments on the manuscript. This work is supported by CNRS - INSU Programme National de Planétologie and Groupement de Recherche en Exobiologie. G. Tinetti is supported by NASA Astrobiology Institute - National Research Council.
Funding AgencyGrant Number
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Programme National Galaxies et Cosmologie (PNCG)UNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Subject Keywords:planets and satellites: general
Issue or Number:1
Record Number:CaltechAUTHORS:20170408-142643779
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Official Citation:The transmission spectrum of Earth-size transiting planets D. Ehrenreich, G. Tinetti, A. Lecavelier de Etangs, A. Vidal-Madjar and F. Sel is A&A, 448 1 (2006) 379-393 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75944
Deposited By: 1Science Import
Deposited On:21 Apr 2017 19:41
Last Modified:09 Mar 2020 13:19

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