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Dynamical Constraints on the Core Mass of Hot Jupiter HAT-P-13b

Buhler, Peter B. and Knutson, Heather A. and Batygin, Konstantin and Fulton, Benjamin J. and Fortney, Jonathan J. and Burrows, Adam and Wong, Ian (2016) Dynamical Constraints on the Core Mass of Hot Jupiter HAT-P-13b. Astrophysical Journal, 821 (1). Art. No. 26. ISSN 0004-637X. doi:10.3847/0004-637X/821/1/26.

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HAT-P-13b is a Jupiter-mass transiting exoplanet that has settled onto a stable, short-period, and mildly eccentric orbit as a consequence of the action of tidal dissipation and perturbations from a second, highly eccentric, outer companion. Owing to the special orbital configuration of the HAT-P-13 system, the magnitude of HAT-P-13b's eccentricity (e_b) is in part dictated by its Love number (k_2_b), which is in turn a proxy for the degree of central mass concentration in its interior. Thus, the measurement of e_b constrains k_2_b and allows us to place otherwise elusive constraints on the mass of HAT-P-13b's core (M_(core,b)). In this study we derive new constraints on the value of e_b by observing two secondary eclipses of HAT-P-13b with the Infrared Array Camera on board the Spitzer Space Telescope. We fit the measured secondary eclipse times simultaneously with radial velocity measurements and find that eb = 0.00700 ± 0.00100. We then use octupole-order secular perturbation theory to find the corresponding k_2_b = 0.31_(-0.05)^(+0.08). Applying structural evolution models, we then find, with 68% confidence, that M_(core,b) is less than 25 Earth masses (M_⊕). The most likely value is M_(core,b) = 11 M_⊕, which is similar to the core mass theoretically required for runaway gas accretion. This is the tightest constraint to date on the core mass of a hot Jupiter. Additionally, we find that the measured secondary eclipse depths, which are in the 3.6 and 4.5 μm bands, best match atmospheric model predictions with a dayside temperature inversion and relatively efficient day–night circulation.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Buhler, Peter B.0000-0002-5247-7148
Knutson, Heather A.0000-0002-0822-3095
Batygin, Konstantin0000-0002-7094-7908
Fulton, Benjamin J.0000-0003-3504-5316
Fortney, Jonathan J.0000-0002-9843-4354
Burrows, Adam0000-0002-3099-5024
Wong, Ian0000-0001-9665-8429
Additional Information:© 2016. The American Astronomical Society. Received 2015 November 5; accepted 2016 February 10; published 2016 April 5. We thank Henry Ngo and Joseph Harrington for insightful discussions. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This material is based on work supported by the National Science Foundation Graduate Research Fellowship under grant No. 2014184874. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors(s) and do not necessarily reflect the views of the National Science Foundation. This work was based in part on observations obtained at the W.M. Keck Observatory using time granted by the University of Hawaii, the University of California, and the California Institute of Technology. We thank the observers who contributed to the measurements reported here and acknowledge the efforts of the Keck Observatory staff. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests.
Funding AgencyGrant Number
NSF Graduate Research Fellowship2014184874
Subject Keywords:methods: data analysis; planets and satellites: atmospheres; planets and satellites: dynamical evolution and stability; planets and satellites: individual (HAT-P-13b) ; planets and satellites: interiors; techniques: photometric
Issue or Number:1
Record Number:CaltechAUTHORS:20160509-131523222
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Official Citation:Peter B. Buhler et al 2016 ApJ 821 26
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:66776
Deposited By: Ruth Sustaita
Deposited On:09 May 2016 21:15
Last Modified:11 Nov 2021 00:02

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