Abstract

Transition discs are prime targets to look for protoplanets and study planet disc interactions. We present VLF/SINFONE observations of PDS 70, a transition disc with a recently claimed embedded protoplanet. We take advantage of the angular and spectral diversity present in our data for an optimal PSF modelling and subtraction using principal component analysis (PCA). We report the redetection of PDS 7() b, both the front and far side of the outer disc edge, and the detection of several extended features in the annular gap. We compare spectral differential imaging applied before (PCA-SARI), and after (PCA-ASDI) angular differential imaging. Our tests suggest that PCA-SADI better recovers extended features, while PCA-ASDI is more sensitive to point sources. We adapted the negative fake companion (NEGFC) technique to infer the astrometry of the companion, and derived r = 193.5 4.9 mas and PA =158.7' 3.0. We used both NEGFC and ANDROMEDA to infer the K-band spectro-photometry of the protoplanet, and found results consistent with recent VLF/SPHERE observations, except for their 2018/02 epoch measurement in the K2 filter. Finally, we derived an upper limit of /1;//, < 1.26 x 10-7 [D114h1 [ MT yr I for the accretion rate of the companion based on an uP adaptation of PCA-SADI/PCA-ASDI around the Dry line (assuming no extinction).