The SPHERE view of the jet and the envelope of RY Tau
  Jets are rarely associated with pre-main-sequence intermediate-mass stars.
Optical and near-IR observations of jet-driving sources are often hindered by
the presence of a natal envelope. Jets around partly embedded sources are a
useful diagnostic to constrain the geometry of the concealed protoplanetary
disk. In fact, the jet-driving mechanisms are affected by both spatial
anisotropies and episodic variations at the (sub-)au scale from the star. We
obtained a rich set of high-contrast VLT/SPHERE observations from 0.6 micron to
2.2 micron of the young intermediate-mass star RY Tau. Given the proximity to
the Sun of this source, our images have the highest spatial resolution ever
obtained for an atomic jet. Optical observations in polarized light show no
sign of the protoplanetary disk detected by ALMA. Instead, we observed a
diffuse signal resembling a remnant envelope with an outflow cavity. The jet is
detected in four spectral lines. The jet appears to be wiggling and its radial
width increasing with the distance is complementary to the shape of the outflow
cavity suggesting a strong jet/envelope interaction. Through the estimated
tangential velocity, we revealed a possible connection between the launching
time of the jet sub-structures and the stellar activity of RY Tau. RY Tau is at
an intermediate stage toward the dispersal of the natal envelope. This source
shows episodic increases of mass accretion/ejection similarly to other known
intermediate-mass stars. The amount of observed jet wiggle is consistent with
the presence of a precessing disk warp or misaligned inner disk that would be
induced by an unseen planetary/sub-stellar companion at sub-/few-au scales. The
high disk mass of RY Tau and of two other jet-driving intermediate-mass stars,
HD163296 and MWC480, suggests that massive, full disks are more efficient at
launching prominent jets.
