Mass Loss from the Exoplanet WASP-12b Inferred from Spitzer Phase Curves
Abstract
The exoplanet WASP-12b is the prototype for the emerging class of ultrahot, Jupiter-mass exoplanets. Past models have predicted – and near-ultraviolet observations have shown – that this planet is losing mass. We present an analysis of two sets of 3.6 and 4.5 μm Spitzer phase curve observations of the system which show clear evidence of infrared radiation from gas stripped from the planet, and the gas appears to be flowing directly toward or away from the host star. This accretion signature is only seen at 4.5 μm, not at 3.6 μm, which is indicative either of CO emission at the longer wavelength or blackbody emission from cool, ≲600 K gas. It is unclear why WASP-12b is the only ultrahot Jupiter to exhibit this mass-loss signature, but perhaps WASP-12b's orbit is decaying as some have claimed, while the orbits of other exoplanets may be more stable; alternatively, the high-energy irradiation from WASP-12A may be stronger than the other host stars. We also find evidence for phase offset variability at the level of 6.4σ (46.2°) at 3.6 μm.
Additional Information
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2019 July 17. Received 2019 July 16; in original form 2019 June 6. Published: 25 July 2019. TJB acknowledges support from the McGill Space Institute Graduate Fellowship, the Natural Sciences and Engineering Research Council of Canada's Postgraduate Scholarships-Doctoral Fellowship, and from the Fonds de recherche du Québec – Nature et technologies through the Centre de Recherche en Astrophysique du Québec. The research leading to these results has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 679633; Exo-Atmos). TJB, LD, and NBC are also affilated with, and supported by, the McGill Space Institute, the Institute for Research on Exoplanets, and the Centre for Research in Astrophysics of Quebec. We have also made use of open-source software provided by the PYTHON, ASTROPY, SCIPY, and MATPLOTLIB communities.Attached Files
Published - stz2018.pdf
Submitted - 1906.04742.pdf
Supplemental Material - stz2018_supplemental_file.pdf
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Additional details
- Eprint ID
- 97311
- Resolver ID
- CaltechAUTHORS:20190722-090919664
- McGill Space Institute
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Fonds de recherche du Québe-Nature et technologies (FRQ-NT)
- 679633
- European Research Council (ERC)
- Created
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2019-07-22Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department, Division of Geological and Planetary Sciences