Period spacings of γ Doradus pulsators in the Kepler field: Rossby and gravity modes in 82 stars
Article
Article Title | Period spacings of γ Doradus pulsators in the Kepler field: Rossby and gravity modes in 82 stars |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Li, Gang (Author), Van Reeth, Timothy (Author), Bedding, Timothy R. (Author), Murphy, Simon J. (Author) and Antoci, Victoria (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 487 (1), pp. 782-800 |
Number of Pages | 19 |
Year | 2019 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stz1171 |
Web Address (URL) | https://academic.oup.com/mnras/article/487/1/782/5481534 |
Abstract | Rossby modes are the oscillations in a rotating fluid, whose restoring force is the Coriolis force. They provide an additional diagnostic to understand the rotation of stars, which complicates asteroseismic modelling. We report 82 γ Doradus stars for which clear period spacing patterns of both gravity and Rossby modes have been detected. The period spacings of both show a quasi-linear relation with the pulsation period, but the slope is negative for the gravity modes and positive for the Rossby modes. Most Rossby modes have k = −2, m = −1. For only one star, a series of k = −1, m = −1 modes is seen. For each pattern, the mean pulsation period, the mean period spacing, and the slope are measured. We find that the slope correlates with the mean period for Rossby mode patterns. The traditional approximation of rotation is used to measure the near-core rotation rate, assuming the star rotates rigidly. We report the near-core rotation rates, the asymptotic period spacings, and the radial orders of excited modes of these 82 main-sequence stars. The near-core rotation rates lie between 0.6 and 2.3d−1. Six stars show surface rotation modulations, among which only KIC 3341457 shows differential rotation, whilst the other five stars have uniform rotations. The radial orders of excited modes show different distributions for the dipole and quadrupole gravity modes versus the Rossby modes. |
Keywords | stars: oscillations; stars: rotation; stars: variables; Astrophysics - Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | University of Sydney |
Aarhus University, Denmark | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q7394/period-spacings-of-doradus-pulsators-in-the-kepler-field-rossby-and-gravity-modes-in-82-stars
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