Tests of the asymptotic large frequency separation of acoustic oscillations in solar-type and red-giant stars

S. Hekker, Y. Elsworth, S. Basu, A. Mazumdar, V. Silva Aguirre, W. J. Chaplin

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

Asteroseismology, i.e. the study of the internal structures of stars via their global oscillations, is a valuable tool to obtain stellar parameters such as mass, radius, surface gravity and mean density. These parameters can be obtained using certain scaling relations which are based on an asymptotic approximation. Usually the observed oscillation parameters are assumed to follow these scaling relations. Recently, it has been questioned whether this is a valid approach, i.e. whether the order of the observed oscillation modes is high enough to be approximated with an asymptotic theory. In this work, we use stellar models to investigate whether the differences between observable oscillation parameters and their asymptotic estimates are indeed significant. We compute the asymptotic values directly from the stellar models and derive the observable values from adiabatic pulsation calculations of the same models. We find that the extent to which the atmosphere is included in the models is a key parameter. Considering a larger extension of the atmosphere beyond the photosphere reduces the difference between the asymptotic and observable values of the large frequency separation. Therefore, we conclude that the currently suggested discrepancies in the scaling relations might have been overestimated. Hence, based on the results presented here we believe that the suggestions of Mosser et al. should not be followed without careful consideration.

Original languageEnglish
Pages (from-to)1668-1673
Number of pages6
JournalRoyal Astronomical Society. Monthly Notices
Volume434
Issue number2
DOIs
Publication statusPublished - 1 Sep 2013

Keywords

  • Asteroseismology
  • Stars: oscillations

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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