VLT/SPHERE performance on a faint target GD 50
1 European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
2 European Southern Observatory, Alonso de Cordova 3107, Vitacura, 19001 Casilla, Santiago 19, Chile
3 Aix-Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
4 Kiel University, Institute of Theoretical Physics and Astrophysics, Leibnizstr. 15, 24118 Kiel, Germany
Received: 24 March 2015
Accepted: 15 June 2015
Context. Little is known about the planetary systems around single white dwarfs, although there is strong evidence that they do exist.
Aims. We performed a pilot study with the extreme-AO system on the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the Very Large Telescopes (VLT) to look for giant planets around a young white dwarf, GD 50.
Methods. We were awarded science verification time on the new ESO instrument SPHERE. Observations were made with the InfraRed Dual-band Imager and Spectrograph in classical imaging mode in H band.
Results. Despite the faintness of the target (14.2 mag in R band), the AO loop was closed and a strehl of 37% was reached in H band. No objects were detected around GD 50. We achieved a 5-sigma contrast of 6.2, 8.0, and 8.25 mag at 0.̋2, 0.̋4, and 0.̋6 and beyond, respectively. We exclude any substellar objects more massive than 4.0 MJ at 6.2 au, 2.9 MJ at 12.4 au, and 2.8 MJ at 18.6 au and beyond. This rivals the previous upper limit set by Spitzer. We further show that SPHERE is the most promising instrument available to search for close-in substellar objects around nearby white dwarfs.
Key words: planets and satellites: detection / white dwarfs
Based on observations made with European Southern Observatory (ESO) telescopes at the La Silla Paranal Observatory under program 60.A-9373(A).
Figure 4 is available in electronic form at http://www.aanda.org
© ESO, 2015