Stellar p-modes oscillation measurements in solar-like star signals: Centauri A as an example

¹ Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
² Dpto. de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain e-mail: [crr;trc]@iac.es

Received: 6 July 2006
Accepted: 28 January 2007

Abstract

Context.This paper deals with the analysis of observational data series of solar-like stars. In dealing with observations of solar-like stellar oscillations from ground observatories, to achieve the necessary level of signal to noise to measure individual acoustic modes in their power spectra it is necessary to have access to large telescopes and preferably more than one used simultaneously at appropriate longitudes. It is very difficult to obtain observing time to cover more than a few day series of data, which usually implies difficulties in obtaining a precise determination of the acoustic frequencies.

Aims.To find the acoustic frequencies of solar-like stars from short duration data series.

Methods.The analysis technique is based on an earlier work by the authors that allows the recovery of the acoustic power spectrum of solar-like stars even in cases with poor S/N ratios. The method is applied to solar data to show how it works and also it is used to re-analyse the recently published ultra-high-precision velocity measurements in α Cen A.

Results.The method is shown to work well with solar observations and allows us to obtain the acoustic frequencies of solar-like stars from short-duration data series with a precision comparable with that obtained from standard methods in longer data series.

Conclusions.This method can be used with currently observed data series to provide useful information on the structure of stars.