Search Publications
Search for brown-dwarf companions of stars
Zucker, S.; Queloz, D.; Sahlmann, J. +7 more
Context. The frequency of brown-dwarf companions in close orbit around Sun-like stars is low compared to the frequency of planetary and stellar companions. There is presently no comprehensive explanation of this lack of brown-dwarf companions.
Aims: By combining the orbital solutions obtained from stellar radial-velocity curves and Hipparcos …
Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs
Quirrenbach, A.; Reffert, S.
Context. The recently completed re-reduction of the Hipparcos data by van Leeuwen (2007a, Astrophysics and Space Science Library, 350) makes it possible to search for the astrometric signatures of planets and brown dwarfs known from radial velocity surveys in the improved Hipparcos intermediate astrometric data.
Aims: Our aim is to put more s…
Distance determination for RAVE stars using stellar models. III. The nature of the RAVE survey and Milky Way chemistry
Gilmore, G.; Freeman, K. C.; Munari, U. +19 more
We apply the method of Burnett & Binney (2010, MNRAS, 407, 339) for the determination of stellar distances and parameters to the internal catalogue of the RAdial Velocity Experiment (RAVE; Steinmetz et al. 2006, AJ, 132, 1645). Subsamples of stars that either have Hipparcos parallaxes or belong to well-studied clusters inspire confidence in th…
The diameter of the CoRoT target HD 49933. Combining the 3D limb darkening, asteroseismology, and interferometry
Morel, P.; Berio, P.; Kervella, P. +21 more
Context. The interpretation of stellar pulsations in terms of internal structure depends on the knowledge of the fundamental stellar parameters. Long-base interferometers permit us to determine very accurate stellar radii, which are independent constraints for stellar models that help us to locate the star in the HR diagram.
Aims: Using a dir…
The debris disk host star HD 61005: a member of the Argus association?
Alcalá, J. M.; Lanzafame, A. C.; Brugaletta, E. +6 more
Context. HD 61005 is a nearby young solar type star that shows a large infrared excess due to a debris disk. The disk has been recently imaged from ground and space, with indications of several components. Some characteristics of the disk suggest the presence of planetary companions around the star, that remain undetected in deep adaptive optics i…
A large Hα line forming region for the massive interacting binaries β Lyrae and υ Sagitarii
Chesneau, O.; Goldfinger, P. J.; Sturmann, J. +16 more
Aims: This study aims at constraining the properties of two interacting binary systems by measuring their continuum-forming region in the visible and the forming regions of some emission lines, in particular Hα, using optical interferometry.
Methods: We have obtained visible medium (R ~ 1000) spectral resolution interferometric observati…
Constructing a Galactic coordinate system based on near-infrared and radio catalogs
Zhu, Z.; Liu, J. -C.; Hu, B.
Context. The definition of the Galactic coordinate system was announced by the IAU Sub-Commission 33b on behalf of the IAU in 1958. An unrigorous transformation was adopted by the Hipparcos group to transform the Galactic coordinate system from the FK4-based B1950.0 system to the FK5-based J2000.0 system or to the International Celestial Reference…
The last revolution of new comets: the role of stars and their detectability
Rickman, H.; Valsecchi, G. B.; Fouchard, M. +1 more
Context. This work is a follow-up of a previous study, where we simulated the dynamical evolution of the Oort Cloud over 5 Gyr with special attention to the injection of comets into observable orbits.
Aims: We wish to clarify how comet injection operates with two types of perturbers: Galactic tides and passing stars. We illustrate why attempt…
HD 5388 b is a 69 MJup companion instead of a planet
Queloz, D.; Sahlmann, J.; Ségransan, D. +1 more
We examined six exoplanet host stars with non-standard Hipparcos astrometric solution, which may be indicative of unrecognised orbital motion. Using Hipparcos intermediate astrometric data, we detected the astrometric orbit of HD 5388 at a significance level of 99.4% (2.7 σ). HD 5388 is a metal-deficient star and hosts a planet candidate with a mi…
The two components of the evolved massive binary LZ Cephei. Testing the effects of binarity on stellar evolution
Bouret, J. -C.; Martins, F.; Donati, J. -F. +2 more
Aims: We present an in-depth study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars.
Methods: We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perform a spectroscopic disentangling and …