On the heat redistribution of the hot transiting exoplanet WASP-18b

Iro, N.; Maxted, P. F. L.

Abstract

The energy deposition and redistribution in hot Jupiter atmospheres is not well understood currently, but is a major factor for their evolution and survival. We present a time dependent radiative transfer model for the atmosphere of WASP-18b which is a massive (10MJup) hot Jupiter (Teq ∼ 2400 K) exoplanet orbiting an F6V star with an orbital period of only 0.94 days.

Our model includes a simplified parametrisation of the day-to-night energy redistribution by a modulation of the stellar heating mimicking a solid body rotation of the atmosphere. We present the cases with either no rotation at all with respect to the synchronously rotating reference frame or a fast differential rotation.

The results of the model are compared to previous observations of secondary eclipses of Nymeyer et al. (Nymeyer, S. et al. [2011]. Astrophys. J. 742, 35) with the Spitzer Space Telescope. Their observed planetary flux suggests that the efficiency of heat distribution from the day-side to the night-side of the planet is extremely inefficient. Our results are consistent with the fact that such large day-side fluxes can be obtained only if there is no rotation of the atmosphere.

Additionally, we infer light curves of the planet for a full orbit in the two Warm Spitzer bandpassses for the two cases of rotation and discuss the observational differences.

Citation

Iro, N., & Maxted, P. F. L. (2013). On the heat redistribution of the hot transiting exoplanet WASP-18b. Icarus, 226(2), 1719-1723. https://doi.org/10.1016/j.icarus.2013.02.027

• Journal Article Type: Article
• Online Publication Date: Mar 7, 2013
• Publication Date: 2013-11
• Deposit Date: Jun 16, 2023
• Journal: Icarus
• Print ISSN: 0019-1035
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 226
• Issue: 2
• Pages: 1719-1723
• DOI: https://doi.org/10.1016/j.icarus.2013.02.027
• Keywords: Space and Planetary Science; Astronomy and Astrophysics; Atmospheres, Structure; Extrasolar planets; Radiative transfer
• Additional Information: This article is maintained by: Elsevier; Article Title: On the heat redistribution of the hot transiting exoplanet WASP-18b; Journal Title: Icarus; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.icarus.2013.02.027; Content Type: article; Copyright: Copyright © 2013 Elsevier Inc. Published by Elsevier Inc. All rights reserved.