Asteroseismology of α Centauri A evidence of rotational splitting

Michael Bazot, F. Bouchy, H. Kjeldsen, S. Charpinet, M. Laymand, S. Vauclair

Research output: Contribution to journalArticle

Abstract

Context. Asteroseismology provides a unique tool for studying stellar interiors. Recently p modes have been detected on the bright solar-like star α Cen A thanks to high-precision radial-velocity measurements. However, a better characterisation of these p modes is clearly needed to constrain theoretical models. Aims. We observed α Cen A during five nights using the HARPS spectrograph in order to improve our knowledge of the seismic properties of this star. Methods. We performed high-precision radial-velocity sequences and computed the acoustic spectrum of α Cen A. Results. We identify 34 p modes with angular degree l = 0-3 in the frequency range 1.8-2.9 mHz and amplitude range 13-48 cms-1, in agreement with previous seismic studies. We find an enhancement of the frequency scatter with the angular degree l that indicates, considering the high inclination axis of α Cen A, rotational splitting and explains the low values of previously suggested mode lifetimes. We also derive new values for the small separations that take the effect of rotational splitting into account. Conclusions. Our seismic study of α Cen A leads to a list of now well-identified p-mode frequencies and shows the importance of taking the rotation into account in order to properly characterise the p modes even in quite short campaigns.

Original languageEnglish (US)
Pages (from-to)295-302
Number of pages8
JournalAstronomy and Astrophysics
Volume470
Issue number1
DOIs
StatePublished - Jul 1 2007

Fingerprint

asteroseismology
seismic property
acoustics
radial velocity
stellar interiors
stars
velocity measurement
night
lists
inclination
spectrographs
frequency ranges
life (durability)
augmentation
effect
method

Keywords

  • Stars: individual: α Centauri A
  • Stars: oscillations
  • Techniques: radial velocities

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Bazot, M., Bouchy, F., Kjeldsen, H., Charpinet, S., Laymand, M., & Vauclair, S. (2007). Asteroseismology of α Centauri A evidence of rotational splitting. Astronomy and Astrophysics, 470(1), 295-302. https://doi.org/10.1051/0004-6361:20065694

Asteroseismology of α Centauri A evidence of rotational splitting. / Bazot, Michael; Bouchy, F.; Kjeldsen, H.; Charpinet, S.; Laymand, M.; Vauclair, S.

In: Astronomy and Astrophysics, Vol. 470, No. 1, 01.07.2007, p. 295-302.

Research output: Contribution to journalArticle

Bazot, M, Bouchy, F, Kjeldsen, H, Charpinet, S, Laymand, M & Vauclair, S 2007, 'Asteroseismology of α Centauri A evidence of rotational splitting', Astronomy and Astrophysics, vol. 470, no. 1, pp. 295-302. https://doi.org/10.1051/0004-6361:20065694
Bazot, Michael ; Bouchy, F. ; Kjeldsen, H. ; Charpinet, S. ; Laymand, M. ; Vauclair, S. / Asteroseismology of α Centauri A evidence of rotational splitting. In: Astronomy and Astrophysics. 2007 ; Vol. 470, No. 1. pp. 295-302.
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