摘要：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 andR-band continuum. Our SMA sub-millimetre interferometry in 880μm 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 theL′-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. InH- andK-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 inHandKis consistent with an actively accreting protoplanet. Hence, we identify V1247 Ori as a unique laboratory for studying companion–disc interactions and disc clearing.
关键词：Key wordsenplanets and satellites: detectionplanets and satellites: formationprotoplanetary disksstars: pre-main sequenceinfrared: planetary systemsstars: individual: V1247 Orionis
