SPOTS: The Search for Planets Orbiting Two Stars

I. Survey description and first observations^⋆,⋆⋆

¹ Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27 8093 Zurich Switzerland
e-mail: thalmann@phys.ethz.ch
² INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
³ Astrophysics Research Center, Queen’s University Belfast, Belfast, UK
⁴ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, 181-8588 Tokyo, Japan
⁵ Department of Astronomical Sciences, Graduate University for Advanced Studies (Sokendai), Mitaka, 181-8858 Tokyo, Japan
⁶ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁷ Department of Physics & Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424, USA
⁸ Observatoire de Meudon, LESIA, Bât. 17, 5 pl. J. Janssen, 92195 Meudon, France
⁹ Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK
¹⁰ Universitätssternwerte München, Scheinerstr. 1, 81679 Munich, Germany
¹¹ Dipartimento di Fisica, University of Padova, via Marzolo 8, 35131 Padova, Italy

Received: 10 July 2014
Accepted: 5 September 2014

Abstract

Direct imaging surveys for exoplanets commonly exclude binary stars from their target lists, leaving a large part of the overall planet demography unexplored. To address this gap in our understanding of planet formation and evolution, we have launched the first direct-imaging survey dedicated to circumbinary planets: SPOTS, the Search for Planets Orbiting Two Stars. We discuss the theoretical context, scientific merit, and technical feasibility of such observations, describe the target sample and observational strategy of our survey, and report on the first results from our pilot survey of 26 targets with the VLT NaCo facility. While we have not found any confirmed substellar companions to date, a number of promising candidate companions remain to be tested for common proper motion in upcoming follow-up observations. We also report on the astrometry of the three resolved binaries in our target sample. This pilot survey constitutes a successful proof of concept for our survey strategy and paves the way for a second stage in the exploratory observations with VLT SPHERE.