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Accurate p-mode measurements of the G0v metal-rich CoRoT target HD 52265

J. Ballot, L. Gizon, R. Samadi, G. Vauclair, O. Benomar, H. Bruntt, B. Mosser, T. Stahn, G. A. Verner, T. L. Campante, R. A. García, S. Mathur, D. Salabert, P. Gaulme, C. Régulo, I. W. Roxburgh, T. Appourchaux, F. Baudin, C. Catala, W. J. Chaplin, S. Deheuvels, E. Michel, M. Bazot, O. L. Creevey, N. Dolez, Y. Elsworth, K. H. Sato, S. Vauclair, M. Auvergne, A. Baglin

Abstract
Context. The star HD 52265 is a G0V metal-rich exoplanet-host star observed in the seismology field of the CoRoT space telescope from November 2008 to March 2009. The satellite collected 117 days of high-precision photometric data on this star, showing that it presents solar-like oscillations. HD 52265 was also observed in spectroscopy with the Narval spectrograph at the same epoch.
Aims. We characterise HD 52265 using both spectroscopic and seismic data.
Methods. The fundamental stellar parameters of HD 52265 were derived with the semi-automatic software VWA, and the projected rotational velocity was estimated by fitting synthetic profiles to isolated lines in the observed spectrum. The parameters of the observed p modes were determined with a maximum-likelihood estimation. We performed a global fit of the oscillation spectrum, over about ten radial orders, for degrees l = 0 to 2. We also derived the properties of the granulation, and analysed a signature of the rotation induced by the photospheric magnetic activity.
Results. Precise determinations of fundamental parameters have been obtained: Teff = 6100 ± 60 K, log g = 4.35 ± 0.09, [M/H] = 0.19 ± 0.05, as well as v sin i = 3.6+0.3-1.0 km s-1.We have measured a mean rotation period Prot = 12.3 ± 0.15 days, and find a signature of differential rotation. The frequencies of 31 modes are reported in the range 1500–2550 µHz. The large separation exhibits a clear modulation around the mean value Δν = 98.3 ± 0.1 µHz. Mode widths vary with frequency along an S-shape with a clear local maximum around 1800 µHz. We deduce lifetimes ranging between 0.5 and 3 days for these modes. Finally, we find a maximal bolometric amplitude of about 3.96 ± 0.24 ppm for radial modes.

Keywords
stars: individual: HD 52265 - asteroseismology - stars: fundamental parameters - stars: rotation - stars: solar-type

Notes
The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain.

Astronomy and Astrophysics
Volume 530, Number of pages A97_1
2011 June

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Fundação para a Ciência e a Tecnologia
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