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The effect of tides on near-core rotation: analysis of 35 Kepler γ Doradus stars in eclipsing and spectroscopic binaries

Li, Gang and Guo, Zhao and Fuller, Jim and Bedding, Timothy R. and Murphy, Simon J. and Colman, Isabel L. and Hey, Daniel R. (2020) The effect of tides on near-core rotation: analysis of 35 Kepler γ Doradus stars in eclipsing and spectroscopic binaries. Monthly Notices of the Royal Astronomical Society, 497 (4). pp. 4363-4375. ISSN 0035-8711.

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We systematically searched for gravity- and Rossby-mode period spacing patterns in Kepler eclipsing binaries with γ Doradus pulsators. These stars provide an excellent opportunity to test the theory of tidal synchronization and angular momentum transport in F- and A-type stars. We discovered 35 systems that show clear patterns, including the spectroscopic binary KIC 10080943. Combined with 45 non-eclipsing binaries with γ Dor components that have been found using pulsation timing, we measured their near-core rotation rates and asymptotic period spacings. We find that many stars are tidally locked if the orbital periods are shorter than 10 d, in which the near-core rotation periods given by the traditional approximation of rotation are consistent with the orbital period. Compared to the single stars, γ Dor stars in binaries tend to have slower near-core rotation rates, likely a consequence of tidal spin-down. We also find three stars that have extremely slow near-core rotation rates. To explain these, we hypothesize that unstable tidally excited oscillations can transfer angular momentum from the star to the orbit, and slow the star below synchronism, a process we refer to as ‘inverse tides’.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Li, Gang0000-0001-9313-251X
Guo, Zhao0000-0002-0951-2171
Fuller, Jim0000-0002-4544-0750
Bedding, Timothy R.0000-0001-5222-4661
Murphy, Simon J.0000-0002-5648-3107
Hey, Daniel R.0000-0003-3244-5357
Additional Information:© 2020 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 2020 July 26. Received 2020 July 24; in original form 2020 May 30. This work was supported by the Australian Research Council through DECRA DE180101104. Funding for the Stellar Astrophysics Centre is provided by the Danish National Research Foundation (grant agreement no.: DNRF106). This work was partially supported by funding from the Center for Exoplanets and Habitable Worlds. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. We appreciate Andrej Prša and Diana Windemuth for providing eccentricities of some EBs. We appreciate Adam Jermyn for sharing his paper draft before publication. DATA AVAILABILITY. The light curves were downloaded from the public data archive at MAST,2 using the PYTHON package LIGHTKURVE (Lightkurve Collaboration et al. 2018).3 The Kepler eclipsing binary catalogue (third revision)4 provided some basic parameters of some eclipsing binaries. The scientific output is available in Table 1 in the article and in its online supplementary material.
Group:Astronomy Department, TAPIR
Funding AgencyGrant Number
Australian Research CouncilDE180101104
Danish National Research FoundationDNRF106
Pennsylvania State UniversityUNSPECIFIED
Eberly College of ScienceUNSPECIFIED
Pennsylvania Space Grant ConsortiumUNSPECIFIED
Subject Keywords:binaries: eclipsing, stars: interiors, stars: oscillations, stars: rotation
Issue or Number:4
Record Number:CaltechAUTHORS:20200915-153608556
Persistent URL:
Official Citation:Gang Li, Zhao Guo, Jim Fuller, Timothy R Bedding, Simon J Murphy, Isabel L Colman, Daniel R Hey, The effect of tides on near-core rotation: analysis of 35 Kepler γ Doradus stars in eclipsing and spectroscopic binaries, Monthly Notices of the Royal Astronomical Society, Volume 497, Issue 4, October 2020, Pages 4363–4375,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105394
Deposited By: George Porter
Deposited On:15 Sep 2020 22:47
Last Modified:15 Sep 2020 22:47

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