Navegando por Autor "Udry, S."
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Artigo A catalog of rotational and radial velocities for evolved stars(Astronomy & Astrophysics, 2014) Medeiros, José Renan de; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M.Rotational and radial velocities have been measured for 1589 evolved stars of spectral types F, G, and K and luminosity classes IV, III, II, and Ib, based on observations carried out with the CORAVEL spectrometers. The precision in radial velocity is better than 0.30 km s−1 per observation, whereas rotational velocity uncertainties are typically 1.0 km s−1 for subgiants and giants and 2.0 km s−1 for class II giants and Ib supergiants.Artigo A planet around the evolved intermediate-mass star HD 110014(Astronomy & Astrophysics, 2009-07-15) Medeiros, José Renan de; Setiawan, J.; Hatzes, A. P.; Pasquini, L.; Girardi, L.; Udry, S.; Döllinger, M. P.; Silva, L. daContext. We found evidence for a sub–stellar companion around the K giant star HD 110014. This cool evolved star, with a spectral type K2III and an estimated mass between 1.9 and 2.4 M, is slightly metal rich with [Fe/H] = 0.19 and a rotational velocity V sin i = 2.0 km s−1. Aims. To search for extrasolar planets around intermediate-mass stars and to improve our knowledge of the nature of radial velocity variations shown by G and K giant stars. Methods. Based on radial velocity analysis, we found evidence for a substellar companion with a planetary mass and long orbital period. The Radial velocity variation of HD 110014 has been monitored from 2000 until 2007 with FEROS at 1.5 m ESO and at the 2.2 m MPG/ESO, HARPS at the 3.6 m ESO and Coralie at 1.2 m Leonard Euler swiss telescopes in La Silla observatory. The radial velocities were computed by using a cross-correlation technique. Line bisector, Hipparcos photometry and chromospheric lines were analyzed to exclude other root-causes for the radial velocity variability. Results. We report the presence of an extrasolar planet around the giant star HD 110014, with an orbital period of 835.48±6.04 days. A Keplerian orbit, with an eccentricity e = 0.462 ± 0.069, yields a minimum mass M sin i = 11.09 MJup. The analysis of the residuals shows evidence for a second RV variability with a period of 130 days and an amplitude of ±100 ms−1. Its nature is not completely clear, but a second planet is a possible explanation.