Thermal emission at 3.6-8 μm from WASP-19b: a hot Jupiter without a stratosphere orbiting an active star

We report detection of thermal emission from the exoplanet WASP-19b at 3.6, 4.5, 5.8 and 8.0 μm. We used the InfraRed Array Camera on the Spitzer Space Telescope to observe two occultations of WASP-19b by its host star. We combine our new detections with previous measurements of WASP-19b's emission at 1.6 and 2.09 μm to construct a spectral energy distribution of the planet's dayside atmosphere. By comparing this with model-atmosphere spectra, we find that the dayside atmosphere of WASP-19b lacks a strong temperature inversion. As WASP-19 is an active star (log R'HK = -4.50 ± 0.03), this finding supports the hypothesis of Knutson, Howard and Isaacson that inversions are suppressed in hot Jupiters orbiting active stars. The available data are unable to differentiate between a carbon-rich and an oxygen-rich atmosphere.

Citation

Anderson , D R , Smith , A M S , Madhusudhan , N , Wheatley , P J , Cameron , A C , Hellier , C , Campo , C , Gillon , M , Harrington , J , Maxted , P F L , Pollacco , D , Queloz , D , Smalley , B , Triaud , A H M J & West , R G 2013 , ' Thermal emission at 3.6-8 μm from WASP-19b: a hot Jupiter without a stratosphere orbiting an active star ' , Monthly Notices of the Royal Astronomical Society , vol. 430 , no. 4 , pp. 3422-3431 . https://doi.org/10.1093/mnras/stt140

Publication

Monthly Notices of the Royal Astronomical Society

Status

Peer reviewed

DOI

https://doi.org/10.1093/mnras/stt140

ISSN

0035-8711

Type

Journal article

Rights

© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://dx.doi.org/10.1093/mnras/stt140