Show simple item record

dc.contributor.authorLecavelier des Etangs, A.
dc.contributor.authorPont, F.
dc.contributor.authorVidal-Madjar, A.
dc.contributor.authorSing, David K.
dc.date.accessioned2014-12-17T10:27:07Z
dc.date.issued2008
dc.description.abstractThe transit spectrum of the exoplanet HD 189733b has recently been obtained between 0.55 and 1.05 m. Here we present an analysis of this spectrum. We develop first-order equations to interpret absorption spectra. In the case of HD 189733b, we show that the observed slope of the absorption as a function of wavelength is characteristic of extinction proportional to the inverse of the fourth power of the wavelength (∝λ−4). Assuming an extinction dominated by Rayleigh scattering, we derive an atmospheric temperature of 1340 ± 150 K. If molecular hydrogen is responsible for the Rayleigh scattering, the atmospheric pressure at the planetary characteristic radius of 0.1564 stellar radius must be 410 ± 30 mbar. However the preferred scenario is scattering by condensate particles. Using the Mie approximation, we find that the particles must have a low value for the imaginary part of the refraction index. We identify MgSiO3 as a possible abundant condensate whose particle size must be between ~10-2 and ~10-1 μm. For this condensate, assuming solar abundance, the pressure at 0.1564 stellar radius is found to be between a few microbars and few millibars, and the temperature is found to be in the range 1340-1540 K, and both depend on the particle size.en_GB
dc.identifier.citationVol. 481 (2), pp. L83 - L86en_GB
dc.identifier.doi10.1051/0004-6361:200809388
dc.identifier.urihttp://hdl.handle.net/10871/16071
dc.language.isoenen_GB
dc.publisherEDP Sciences for European Southern Observatory (ESO)en_GB
dc.relation.urlhttp://dx.doi.org/10.1051/0004-6361:200809388en_GB
dc.subjectstars: planetary systemsen_GB
dc.subjectscatteringen_GB
dc.subjecttechniques: spectroscopicen_GB
dc.subjectstars: individual: HD 189733ben_GB
dc.titleRayleigh scattering in the transit spectrum of HD 189733ben_GB
dc.typeArticleen_GB
dc.date.available2014-12-17T10:27:07Z
dc.identifier.issn0004-6361
dc.descriptionCopyright © ESO 2008en_GB
dc.identifier.eissn1432-0746
dc.identifier.journalAstronomy and Astrophysicsen_GB


Files in this item

This item appears in the following Collection(s)

Show simple item record