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Mass Loss from the Exoplanet WASP-12b Inferred from Spitzer Phase Curves

Bell, Taylor J. and Zhang, Michael and Cubillos, Patricio E. and Dang, Lisa and Fossati, Luca and Todorov, Kamen O. and Cowan, Nicolas B. and Deming, Drake and Zellem, Robert T. and Stevenson, Kevin B. and Crossfield, Ian J. M. and Dobbs-Dixon, Ian and Fortney, Jonathan J. and Knutson, Heather A. and Line, Michael R. (2019) Mass Loss from the Exoplanet WASP-12b Inferred from Spitzer Phase Curves. Monthly Notices of the Royal Astronomical Society, 489 (2). pp. 1995-2013. ISSN 0035-8711.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Bell, Taylor J.0000-0003-4177-2149
Zhang, Michael0000-0002-0659-1783
Cubillos, Patricio E.0000-0002-1347-2600
Dang, Lisa0000-0003-4987-6591
Fossati, Luca0000-0003-4426-9530
Todorov, Kamen O.0000-0002-9276-8118
Cowan, Nicolas B.0000-0001-6129-5699
Deming, Drake0000-0001-5727-4094
Zellem, Robert T.0000-0001-7547-0398
Stevenson, Kevin B.0000-0002-7352-7941
Crossfield, Ian J. M.0000-0002-1835-1891
Dobbs-Dixon, Ian0000-0002-4989-6501
Fortney, Jonathan J.0000-0002-9843-4354
Knutson, Heather A.0000-0002-0822-3095
Line, Michael R.0000-0002-2338-476X
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 ( 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.
Group:Astronomy Department
Funding AgencyGrant Number
McGill Space InstituteUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Fonds de recherche du Québe-Nature et technologies (FRQ-NT)UNSPECIFIED
European Research Council (ERC)679633
Subject Keywords:accretion, accretion discs – techniques: photometric – planets and satellites: individual (WASP-12b) – planet–star interactions
Issue or Number:2
Record Number:CaltechAUTHORS:20190722-090919664
Persistent URL:
Official Citation:Taylor J Bell, Michael Zhang, Patricio E Cubillos, Lisa Dang, Luca Fossati, Kamen O Todorov, Nicolas B Cowan, Drake Deming, Robert T Zellem, Kevin B Stevenson, Ian J M Crossfield, Ian Dobbs-Dixon, Jonathan J Fortney, Heather A Knutson, Michael R Line, Mass loss from the exoplanet WASP-12b inferred from Spitzer phase curves, Monthly Notices of the Royal Astronomical Society, Volume 489, Issue 2, October 2019, Pages 1995–2013,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97311
Deposited By: Tony Diaz
Deposited On:22 Jul 2019 16:18
Last Modified:20 Apr 2020 08:47

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