Imaging the disc rim and a moving close-in companion candidate in the pre-transitional disc of V1247 Orionis
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.
Astronomy and Astrophysics
- Pub Date:
- January 2019
- planets and satellites: detection;
- planets and satellites: formation;
- protoplanetary disks;
- stars: pre-main sequence;
- infrared: planetary systems;
- stars: individual: V1247 Orionis;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- 17 pages, 14 figures