Asteroseismology of alpha Cen A. Evidence of rotational splitting

Abstract

Asteroseismology provides a unique tool for studying stellar interiors. Recently p modes have been detected on the bright solar-like star alpha Cen A thanks to high-precision radial-velocity measurements. However a better characterisation of these p modes is clearly needed to constrain theoretical models. We observed alpha Cen A during five nights using the HARPS spectrograph in order to improve our knowledge of the seismic properties of this star. We performed high-precision radial-velocity sequences and computed the acoustic spectrum of alpha Cen A. 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 cm/s, 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 alpha 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 . Our seismic study of alpha 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.

10 pages, 9 figures. To be published in A&A

References in corpus (2)

• Rotation speed and stellar axis inclination from p modes: How CoRoT would see other suns
• Frequency, splitting, linewidth and amplitude estimates of low-l p modes of alpha Cen A: analysis of WIRE photometry

Cited by in corpus (21)

• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Correcting stellar oscillation frequencies for near-surface effects
• A Stellar Model-fitting Pipeline for Asteroseismic Data from the Kepler Mission
• Solar-like oscillations in the G8 V star tau Ceti
• Radial Velocity Fitting Challenge. I. Simulating the data set including realistic stellar radial-velocity signals
• Reinvestigating $\alpha$ Cen AB in light of asteroseismic forward and inverse methods
• Analysis of 70 Ophiuchi AB including seismic constraints
• Convective boundary mixing in low- and intermediate-mass stars I. Core properties from pressure-mode asteroseismology
• The Current Status of Asteroseismology
• Asteroseismology of Procyon with SOPHIE
• Age-dating the young open cluster UBC 1 with g-mode asteroseismology, gyrochronology, and isochrone fitting
• Modelling stellar activity with Gaussian process regression networks
• EMISSA -- Exploring Millimeter Indicators of Solar-Stellar Activity I. The Initial mm-cm Main Sequence Star Sample
• High-frequency modes in solar-like stars
• Europium as a lodestar: diagnosis of radiogenic heat production in terrestrial exoplanets
• Coronal X-ray emission and planetary irradiation in HD 209458
• Developement of a stabilized Fabry-Perot etalon based calibrator for Hanle Echelle Spectrograph (HESP)
• Noise Sources in Photometry and Radial Velocities
• On the nature of the core of $\alpha$ Centauri A: the impact of the metallicity mixture
• What is the mass of alpha Cen B b?
• Current Issues in Asteroseismology