Imaging the disc rim and a moving close-in companion candidate in the pre-transitional disc of V1247 Orionis^★

¹ University of Exeter, Astrophysics Group, School of Physics, Stocker Road, Exeter EX4 4QL, UK
e-mail: willson@astro.gsu.edu
² Instituut voor Sterrenkunde (IvS), KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
³ Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Ave, Ann Arbor, MI 48109, USA
⁴ Instituto de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretana 1111, Valparaíso, Chile
⁵ Department of Physics, University of Cincinnati, Cincinnati, OH 45221, USA
⁶ Space Science Institute, 475 Walnut St., Suite 205, Boulder, CO 80301, USA
⁷ Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia
⁸ Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA
⁹ Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹⁰ Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA
¹¹ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
¹² Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinijuku-ku, Tokyo 163-8677, Japan

Received: 6 December 2016
Accepted: 25 October 2018

Abstract

Context. V1247 Orionis harbours a pre-transitional disc with a partially cleared gap. Earlier interferometric and polarimetric observations revealed strong asymmetries both in the gap region and in the outer disc. The presence of a companion was inferred to explain these asymmetric structures and the ongoing disc clearing.

Aims. Using an extensive set of multi-wavelength and multi-epoch observations we aimed to identify the origin of the previously detected asymmetries.

Methods. We have observed V1247 Ori at three epochs spanning ~678 days using sparse aperture masking interferometry with Keck/NIRC2 and VLT/NACO. In addition, we search for signs of accretion through VLT/SPHERE-ZIMPOL spectral differential imaging in Hα and R-band continuum. Our SMA sub-millimetre interferometry in 880 μm continuum and in the CO(3-2) line allows us to constrain the orientation and direction of rotation of the outer disc.

Results. We find the L′-band emission to be dominated by static features which trace forward-scattered dust emission from the inner edge of the outer disc located to the north-east. In H- and K-bands, we see evidence for a companion candidate that moved systematically by 45° within the first ~345 days. The separation of the companion candidate is not well constrained, but the observed position angle change is consistent with Keplerian motion of a body located on a 6 au orbit. From the SMA CO moment map, the location of the disc rim, and the detected orbital motion, we deduced the three-dimensional orientation of the disc. We see no indication of accretion in Hα and set upper limits for an accreting companion.

Conclusions. The measured contrast of the companion candidate in H and K is consistent with an actively accreting protoplanet. Hence, we identify V1247 Ori as a unique laboratory for studying companion–disc interactions and disc clearing.