EDP Sciences
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Volume 493, Number 2, January II 2009
Page(s) L21 - L25
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200811325
Published online 11 December 2008

A&A 493, L21-L25 (2009)
DOI: 10.1051/0004-6361:200811325


A probable giant planet imaged in the $\mathsf{\beta}$ Pictoris disk

VLT/NaCo deep L $\mathsf{'}$-band imaging
A.-M. Lagrange1, D. Gratadour2, G. Chauvin1, T. Fusco3, D. Ehrenreich1, D. Mouillet1, G. Rousset2, 3, D. Rouan2, F. Allard4, É. Gendron2, J. Charton1, L. Mugnier3, P. Rabou1, J. Montri3, and F. Lacombe2

1  Laboratoire d'Astrophysique de l'Observatoire de Grenoble, Université Joseph Fourier, CNRS (UMR 5571), BP 53, 38041 Grenoble, France
    e-mail: anne-marie.lagrange@obs.ujf-grenoble.fr
2  Laboratoire d'Études Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, CNRS (UMR 8109), Université Pierre et Marie Curie, Université Paris-Diderot, 5 place Jules Janssen, 92190 Meudon, France
3  Office National d'Études et de Recherches Aérospatiales, 29 avenue de la Division Leclerc, 92322 Châtillon, France
4  Centre de Recherche Astronomique de Lyon, CNRS (UMR 5574), Université Claude Bernard, École Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 7, France

Received 10 November 2008 / Accepted 18 November 2008

Context. Since the discovery of its dusty disk in 1984, $\beta$ Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~10 AU. However, no planets have been detected around this star so far.
Aims. Our goal was to investigate the close environment of $\beta$ Pic, searching for planetary companion(s).
Methods. Deep adaptive-optics L'-band images of $\beta$ Pic were recorded using the NaCo instrument at the Very Large Telescope.
Results. A faint point-like signal is detected at a projected distance of $\simeq$8 AU from the star, within the northeastern extension of the dust disk. Various tests were made to rule out possible instrumental or atmospheric artefacts at a good confidence level. The probability of a foreground or background contaminant is extremely low, based in addition on the analysis of previous deep HST images. Its L'=11.2 apparent magnitude would indicate a typical temperature of ~1500 K and a mass of ~8  $M_{\rm Jup}$. If confirmed, it could explain the main morphological and dynamical peculiarities of the $\beta$ Pic system. The present detection is unique among A-stars by the proximity of the resolved planet to its parent star. Its closeness and location inside the $\beta$ Pic disk suggest a formation process by core accretion or disk instabilities rather than binary-like formation processes.

Key words: instrumentation: adaptive optics -- stars: early-type -- stars: planetary systems -- stars: individual: $\beta$ Pic

© ESO 2009