Brown dwarf characterization with Emphasis Type="

Authors: J C Morales JP Beaulieu V Coudé du Foresto P Drossart G Tinetti

Publish Date: 2015/01/18

Volume: 40, Issue: 2-3, Pages: 733-751

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Abstract

The Exoplanet Characterization Observatory EChO is a space mission concept dedicated to the analysis of exoplanet atmospheres using lowresolution spectroscopy in the infrared region between 055 and 11 μm A fraction of its time will be used for ancillary science We discuss here the prospect of a small survey of L and Ttype brown dwarfs These cold objects show properties comparable to those of giant planets with the advantage of being brighter and not perturbed by host stars therefore they are very useful to understand processes and properties of planet atmospheres At the same time brown dwarfs still pose some challenges to stellar models that must include the formation of clouds and sedimentation processes that occur at the low temperatures of these objects Hence our aim is to build up an homogeneous catalogue of spectra of brown dwarfs as well as to characterize the spectral variability observed on some of them which is attributed to the presence of clouds in their atmospheres We demonstrate that EChO could provide the spectra of brown dwarfs between 1 and 11 μm with enough accuracy to reach these goals We also present the current number of known brown dwarfs and we suggest a list of possible targets although future surveys will probably provide better targets at the time of EChO launch if the mission is selectedWe are grateful to F Allard for advice on the use of Phoenix stellar atmosphere models and to A Burgasser and M C Cushing for kindly providing the Jupiter IRTF and CIRS data We also thank the referee for a thorough and very helpful review of the paper This research has benefitted from the M L T and Y dwarf compendium housed at DwarfArchivesorg We are grateful to CNES for financial support

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