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

Anderson, D. R.; Smith, A. M. S.; Madhusudhan, N.; Wheatley, P. J.; Collier Cameron, A.; 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.

Abstract

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., Collier Cameron, A., Hellier, C., …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, 430(4), 3422-3431. https://doi.org/10.1093/mnras/stt140

• Journal Article Type: Article
• Online Publication Date: Feb 20, 2013
• Publication Date: Apr 21, 2013
• Deposit Date: Jun 16, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 0035-8711
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 430
• Issue: 4
• Pages: 3422-3431
• DOI: https://doi.org/10.1093/mnras/stt140
• Keywords: Space and Planetary Science, Astronomy and Astrophysics; methods: data analysis, techniques: photometric, occultations, planets and satellites: atmospheres, planets and satellites: individual: WASP-19b, stars: individual: WASP-19