Asteroseismology of Procyon with SOPHIE ^*,**

¹ LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France e-mail: benoit.mosser@obspm.fr
² Institut d'Astrophysique de Paris, CNRS, Université Pierre et Marie Curie, 98 bld Arago, 75014 Paris, France
³ Service d'Aéronomie du CNRS, BP 3, 91371 Verrières le Buisson, France
⁴ Institut d'Astrophysique Spatiale, Université Paris XI-CNRS, Bâtiment 121, 91405 Orsay Cedex, France
⁵ Laboratoire Cassiopée, UMR CNRS 6202, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
⁶ DAPNIA/DSM/Service d'Astrophysique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France

Received: 23 July 2007
Accepted: 15 November 2007

Abstract

Context.This paper reports a 9-night asteroseismic observation program conducted in January 2007 with the new spectrometer sophie at the OHP 193-cm telescope, on the F5 IV-V target Procyon A.

Aims.This first asteroseismic program with sophie was intended to test the performance of the instrument with a bright but demanding asteroseismic target and was part of a multisite network.

Methods.The sophie spectra have been reduced with the data reduction software provided by OHP. The Procyon asteroseismic data were then analyzed with statistical tools. The asymptotic analysis has been conducted considering possible curvature in the échelle diagram analysis.

Results.These observations have proven the efficient performance of sophie used as an asteroseismometer, and succeed in a clear detection of the large spacing. An échelle diagram based on the 54-μHz spacing shows clear ridges. Identification of the peaks exhibits large spacings varying from about 52 μHz to 56 μHz. Outside the frequency range [0.9, 1.0 mHz] where the identification is confused, the large spacing increases at a rate of about Hz. This may explain some of the different values of the large spacing obtained by previous observations.