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Solar Physics

, Volume 220, Issue 2, pp 207–228 | Cite as

Simulating stochastically excited oscillations: The mode lifetime of ξ Hya

  • Dennis Stello
  • Hans Kjeldsen
  • Timothy R. Bedding
  • Joris De Ridder
  • Conny Aerts
  • Fabien Carrier
  • SØren Frandsen
Article

Abstract

The discovery of solar-like oscillations in the giant star ξ Hya (G7 III) was reported by Frandsen et al. (2002). Their frequency analysis was very limited due to alias problems in the data set (caused by single-site observations). The extent to which the aliasing affected their analysis was unclear due to the unknown damping time of the stellar oscillation modes. In this paper we describe a simulator created to generate time series of stochastically excited oscillations, which takes as input an arbitrary window function and includes both white and non-white noise. We also outline a new method to compare a large number of simulated time series with an observed time series to determine the damping time, amplitude, and limited information on the degree of the stochastically excited modes. For ξ Hya we find the most likely amplitude to be ∼ 2 m s−1, in good agreement with theory (Houdek and Gough, 2002), and the most likely damping time to be ∼ 2 days, which is much shorter than the theoretical value of 15–20 days calculated by Houdek and Gough (2002).

Keywords

Time Series Simulated Time Frequency Analysis Oscillation Mode Aliasing 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Dennis Stello
    • 1
    • 2
  • Hans Kjeldsen
    • 2
    • 3
  • Timothy R. Bedding
    • 1
  • Joris De Ridder
    • 4
  • Conny Aerts
    • 5
  • Fabien Carrier
    • 5
  • SØren Frandsen
    • 2
  1. 1.School of PhysicsUniversity of SydneyAustralia
  2. 2.Department of Physics and AstronomyUniversity of AarhusAarhus CDenmark
  3. 3.Teoretisk Astrofysik CenterDanmarks GrundforskningsfondAarhus CDenmark
  4. 4.Instituut voor SterrenkundeKatholieke Universiteit LeuvenLeuvenBelgium
  5. 5.Observatoire de Genève,SauvernySwitzerland

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