Кл.слова (ненормированные):
methods: numerical -- planets and satellites: atmospheres -- planets and satellites: individual (WASP-49b) -- techniques: spectroscopic
Аннотация: The strong, nearly wavelength-independent absorption cross section of aerosols produces featureless exoplanet transmission spectra, limiting our ability to characterize their atmospheres. Here, we show that even in the presence of featureless spectra, we can still characterize certain atmospheric properties. Specifically, we constrain the upper and lower pressure boundaries of aerosol layers, and present plausible composition candidates. We study the case of the bloated Saturn-mass planet WASP-49 b, where near-infrared observations reveal a flat transmission spectrum between 0.7 and 1.0 ?m. First, we use a hydrodynamic upper-atmosphere code to estimate the pressure reached by the ionizing stellar high-energy photons at 10-8 bar, setting the upper pressure boundary where aerosols could exist. Then, we combine HELIOS and Pyrat Bay radiative-transfer models to constrain the temperature and photospheric pressure of atmospheric aerosols, in a Bayesian framework. For WASP-49 b, we constrain the transmission photosphere (hence, the aerosol deck boundaries) to pressures above 10-5 bar (100?solar metallicity), 10-4 bar (solar), and 10-3 bar (0.1?solar) as the lower boundary, and below 10-7 bar as the upper boundary. Lastly, we compare condensation curves of aerosol compounds with the planet's pressure-temperature profile to identify plausible condensates responsible for the absorption. Under these circumstances, we find these candidates: Na2S (at 100? solar metallicity); Cr and MnS (at solar and 0.1?solar); and forsterite, enstatite, and alabandite (at 0.1?solar). © 2017. The American Astronomical Society. All rights reserved.
Scopus,
Смотреть статью,
WOS
Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, Austria
Federal Research Center Krasnoyarsk Science Center SB RAS, Institute of Computational Modelling, Krasnoyarsk, Russian Federation
Center for Space and Habitability, University of Bern, Sidlerstrasse 5, Bern, Switzerland
Institut fur Geophysik und Meteorologie, Universitat zu Koln, Albertus-Magnus-Platz, Koln, Germany
Max Planck Institute for Astronomy, Konigstuhl 17, Heidelberg, Germany
Department of Astrophysics, University of Vienna, Turkenschanzstrasse 17, Vienna, Austria
Geneva Observatory, University of Geneva, ch. de Maillettes 51, Versoix, Switzerland
Доп.точки доступа:
Cubillos, P. E.; Fossati, L.; Erkaev, N. V.; Malik, M.; Tokano, T.; Lendl, M.; Johnstone, C. P.; Lammer, H.; Wyttenbach, A.