Searching for companions down to 2 AU from β Pictoris using the L′-band AGPM coronagraph on VLT/NACO

¹ Département d’Astrophysique, Géophysique et Océanographie, Université de Liège, Allée du Six Août 17, 4000 Liège, Belgium
e-mail: absil@astro.ulg.ac.be
² European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago, Chile
³ UJF-Grenoble 1/CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France
⁴ LESIA-Observatoire de Paris, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, 5 Pl. J. Janssen, 92195 Meudon, France

Received: 25 September 2013
Accepted: 6 November 2013

Abstract

Context. The orbit of the giant planet discovered around β Pic is slightly inclined with respect to the outer parts of the debris disc, which creates a warp in the inner debris disc. This inclination might be explained by gravitational interactions with other planets.

Aims. We aim to search for additional giant planets located at smaller angular separations from the star.

Methods. We used the new L′-band AGPM coronagraph on VLT/NACO, which provides an exquisite inner working angle. A long observing sequence was obtained on β Pic in pupil-tracking mode. To derive sensitivity limits, the collected images were processed using a principal-component analysis technique specifically tailored to angular differential imaging.

Results. No additional planet is detected down to an angular separation of 0.''2with a sensitivity better than 5 M_Jup. Meaningful upper limits (<10 M_Jup) are derived down to an angular separation of 0.''1, which corresponds to 2 AU at the distance of β Pic.