[en] Context: We conducted a 5-night observing run with the spectrometer harps at the ESO 3.6-m telescope in August 2006, to continue exploring the asteroseismic properties of F-type stars. In fact, Doppler observations of F-type on the main sequence are demanding and remain currently limited to a single case (HD 49933). Comparison with photometric results obtained with the CoRoT space mission (Convection, Rotation and planetary Transits) on similar stars will be possible with an enhanced set of observations. Aims: We selected the 4th magnitude F8V star HD 203608 to investigate the oscillating properties of a low-metallicity star of the old galactic disk. Methods: We reduced the spectra with the on-line data reduction software provided by the instrument. We developed a new statistical approach for extracting the significant peaks in the Fourier domain. Results: The oscillation spectrum shows a significant excess power in the frequency range [1.5, 3.0 mHz]. It exhibits a large spacing of about 120.4 muHz at 2.5 mHz. Variations of the large spacing with frequency are clearly identified, which require an adapted asymptotic development. The modes identification is based on the unambiguous signature of 15 modes with l = 0 and 1. Conclusions: These observations show the potential diagnostic of asteroseismic constraints. Including them in the stellar modeling significantly enhances the precision on the physical parameters of HD 203608, resulting in a much more precise position in the HR diagram. The age of the star is now determined in the range 7.25±0.07 Gyr. Based on observations obtained with the harps échelle spectrometer mounted on the 3.6-m telescope at ESO-La Silla Observatory (Chile), programme 077.D-0720. Data corresponding to Figs. [see full textsee full textsee full text], [see full textsee full textsee full text], and Table [see full textsee full textsee full text] are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/488/635
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Mosser, B.; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
Deheuvels, S.; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
Michel, Eric
Thévenin, F.; Laboratoire Cassiopée, Université de Nice Sophia Antipolis, Observatoire de la Côte d'Azur, CNRS, BP 4229, 06304 Nice Cedex 4, France
Dupret, Marc-Antoine ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique
Samadi, R.; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
Barban, C.; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
Goupil, M. J.; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
Language :
English
Title :
HD 203608, a quiet asteroseismic target in the old galactic disk
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