O. Creevey

Publications (4)4.03 Total impact

• Source

  Available from: Claude Catala

  Article: 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, [......], S. Deheuvels, E. Michel, M. Bazot, O. Creevey, N. Dolez, Y. Elsworth, K. H. Sato, S. Vauclair, M. Auvergne, A. Baglin
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  ABSTRACT: 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. We characterise HD 52265 using both spectroscopic and seismic data. 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. 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 vsini = 3.6 +0.3 -1.0 km/s. We have measured a mean rotation period P_rot = 12.3 +- 0.15 days, and find a signature of differential rotation. The frequencies of 31 modes are reported in the range 1500-2550 micro-Hz. The large separation exhibits a clear modulation around the mean value = 98.3 +- 0.1 micro-Hz. Mode widths vary with frequency along an S-shape with a clear local maximum around 1800 micro-Hz. 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.
  05/2011;
• Source

  Available from: arxiv.org

  Article: Preparing the COROT Space Mission: New Variable Stars in the Galactic Anticenter Direction

  E. Poretti, R. Alonso, P. J. Amado, J. A. Belmonte, R. Garrido, S. Martín-Ruiz, K. Uytterhoeven, C. Catala, Y. Lebreton, E. Michel, J. C. Suárez, C. Aerts, O. Creevey, M. J. Goupil, L. Mantegazza, P. Mathias, M. Rainer, and W. W. Weiss
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  ABSTRACT: The activities related to the preparation of the asteroseismic, photometric space mission COROT are described. Photoelectric observations, wide-field CCD photometry, uvbyβ calibrations, and further time series have been obtained at different observatories and telescopes. They have been planned to complete the COROT program in the direction of the Galactic anticenter. In addition to suitable asteroseismic targets covering the different evolutionary stages between zero-age main sequence and terminal-age main sequence, we discovered several other variable stars, both pulsating and geometric. We compared results on the incidence of variability in the Galactic center and anticenter directions. Physical parameters have been obtained, and evolutionary tracks fitting them have been calculated. The peculiarities of some individual stars are pointed out.
  The Astronomical Journal 12/2007; 129(5):2461. · 4.03 Impact Factor
• Source

  Available from: ArXiv

  Article: Pulsational frequencies of the eclipsing delta-Scuti star HD 172189

  J. E. S. Costa, E. Michel, J. Pena, O. Creevey, Z. P. Li, M. Chevreton, J. A. Belmonte, M Alvarez, L. Fox Machado, L. Parrao, F. Perez Hernendez, A. Fernandez, J. R. Fremy, S. Pau, R. Alonso
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  ABSTRACT: The eclipsing delta-Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. 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. From a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign we have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level in the range between 100-300 uHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system. Comment: 6 pages, 7 figures
  06/2007;
• Article: Pulsational frequencies of the eclipsing $\delta$ Scuti star HD 172189. Results of the STEPHI XIII campaign

  J. E. S. Costa, E. Michel, J. Peña, O. Creevey, Z. P. Li, M. Chevreton, J. A. Belmonte, M Alvarez, L. Fox Machado, L. Parrao, F. Pérez Hernéndez, A. Fernández, J. R. Fremy, S. Pau, R. Alonso
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  ABSTRACT: Context.The eclipsing $\delta$ 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 $\mu$Hz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.
  http://dx.doi.org/10.1051/0004-6361:20065784.
• Article: Pulsational frequencies of the eclipsingScuti star HD 172189. Results of the STEPHI XIII campaign

  J. E. S. Costa, E. Michel, J. Pena, O. Creevey, Z. P. Li, M. Chevreton, J. A. Belmonte, M. Alvarez, L. Fox Machado, L. Parrao, F. Perez Hernendez, A. Fernandez
  [show abstract] [hide abstract]
  ABSTRACT: Context. The eclipsingδ 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 aster oseismological 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 asteroseism ological 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 confidenc e level of 99% and a seventh with a 65% confidence level, in the range between 100− 300� Hz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.