EDP Sciences
Free access
Volume 459, Number 3, December I 2006
Page(s) 955 - 963
Section Planets and planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:20054710

A&A 459, 955-963 (2006)
DOI: 10.1051/0004-6361:20054710

New constrains on Gliese 86 B

VLT near infrared coronographic imaging survey of planetary hosts
A.-M. Lagrange1, H. Beust1, S. Udry2, G. Chauvin3, and M. Mayor2

1  Laboratoire d'Astrophysique de Grenoble, Université J. Fourier, BP 53, 38041 Grenoble Cedex 9, France
    e-mail: lagrange@obs.ujf-grenoble.fr
2  Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
3  ESO Casilla 19001, Santiago 19, Chile

(Received 16 December 2005 / Accepted 1 March 2006)

Aims.We present the results of multi epoch imaging observations of the companion to the planetary host Gliese 86. Associated with radial velocity measurements, this study aimed at dynamically characterizing with the orbital properties and the mass of this companion (hereafter Gliese 86 B), but also at investigating the possible history of this particular system.
Methods.We used the adaptive optics instrument NACO at the ESO Very Large Telescope to obtain deep coronographic imaging to obtain new photometric and astrometric measurements of Gliese 86 B.
Results.Part of the orbit is resolved. The photometry of Gl 86  B indicates colors compatible with a ~70 Jupiter mass brown dwarf or a white dwarf. Both types of objects fit the available, still limited astrometric data. If we attribute the long term radial velocity residual drift observed for Gl 86  A to B, then the mass of the latter object is ${\simeq}0.5\,M_\odot$. We analyse both astrometric and radial velocity data to propose first orbital parameters for Gl 86  B. Assuming Gl 86  B is a ${\simeq}0.5\,M_\odot$ white dwarf, we explore the constraints induced by this hypothesis and refine the parameters of the system.

Key words: stars: individual: Gliese 86 -- stars: low mass, brown dwarfs -- stars: planetary systems -- instrumentation: adaptive optics

© ESO 2006