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Published October 2018 | Published + Accepted Version
Journal Article Open

Sensitivity of gravito-inertial modes to differential rotation in intermediate-mass main-sequence stars

Abstract

Context. While rotation has a major impact on stellar structure and evolution, its effects are not well understood. Thanks to high-quality and long-time base photometric observations obtained with recent space missions, we are now able to study stellar rotation more precisely. Aims. We aim to constrain radial differential rotation profiles in γ Doradus (γ Dor) stars, and to develop new theoretical seismic diagnosis for such stars with rapid and potentially non-uniform rotation. Methods. We have derived a new asymptotic description which accounts for the impact of weak differential near-core rotation on gravity-mode period spacings. The theoretical predictions are illustrated from pulsation computations with the code GYRE and compared with observations of γ Dor stars. When possible, we also derived the surface rotation rates in these stars by detecting and analysing signatures of rotational modulation, and computed the core-to-surface rotation ratios. Results. Stellar rotation must be strongly differential before its effects on period spacing patterns can be detected, unless multiple period spacing patterns can be compared. Six stars in our sample exhibit a single unexplained period spacing pattern of retrograde modes. We hypothesise that these are Yanai modes. Finally, we find signatures of rotational spot modulation in the photometric data of eight targets. Conclusions. If only one period spacing pattern is detected and analysed for a star, it is difficult to detect differential rotation. A rigidly rotating model will often provide the best solution. Differential rotation can only be detected when multiple period spacing patterns have been found for a single star or its surface rotation rate is known as well. This is the case for eight of the stars in our sample, revealing surface-to-core rotation ratios between 0.95 and 1.05.

Additional Information

© 2018 ESO. Article published by EDP Sciences. Received 26 January 2018; Accepted 26 June 2018; Published online 09 October 2018. TVR is grateful for the kind hospitality and opportunity to perform part of this research at the Kavli Institute of Theoretical Physics, University of California at Santa Barbara, USA. The research leading to these results has received funding from the Research Foundation Flanders (FWO, Belgium, under grant agreements G.0B69.13 and V4.272.17N), from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreements No. 670519: MAMSIE, and No. 647383: SPIRE), from the National Science Foundation of the United States under grant NSF PHY-1748958, from the Belgian Science Policy Office (Belspo) under ESA/PRODEX grant "PLATO mission development", from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO) under the grant agreement G0H5416N (ERC Opvangproject), and from PLATO CNES grant at CEA-Saclay. We gratefully acknowledge (partial) support from the Australian Research Council, and from the Danish National Research Foundation (Grant DNRF106) through its funding for the Stellar Astrophysics Centre (SAC). AGH acknowledges funding support from Spanish public funds for research under project ESP2015-65712-C5-5-R (MINECO/FEDER), from project RYC-2012-09913 under the "Ramónn y Cajal" programme of the Spanish MINECO, from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the fellowship SFRH/BPD/80619/2011 and from the European Council Project SPACEINN (FP7-SPACE-2012-312844). JG and RHDT acknowledge support from National Science Foundation grants AST 1716436 and ACI 1663696. We are grateful to Bill Paxton and his collaborators for their valuable work on the stellar evolution code MESA. Funding for the Kepler mission is provided by NASA's Science Mission Directorate. We thank the whole team for the development and operations of the mission. This research made use of the SIMBAD database, operated at CDS, Strasbourg, France, and the SAO/NASA Astrophysics Data System. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France.

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Published - aa32718-18.pdf

Accepted Version - 1806.03586.pdf

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Additional details

Created:
August 19, 2023
Modified:
October 18, 2023