Pulsational frequencies of the eclipsing δ Scuti star HD 172189. Results of the STEPHI XIII campaign^*

¹ Observatoire de Paris, LESIA, FRE 2461, 92195 Meudon, France e-mail: 00112740@ufrgs.br
² Instituto de Astronomía - Universidad Nacional Autónoma de México, Ap.P. 877, Ensenada, BC, Mexico
³ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
⁴ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, P.R. China

Received: 8 June 2006
Accepted: 22 February 2007

Abstract

Context.The eclipsing δ Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission.

Aims.The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models.

Methods.We performed a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign.

Results.We have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level of 65%, in the range between 100-300 μHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.