External or internal companion exciting the spiral arms in CQ Tau?

ABSTRACT We present new high-contrast images in near-infrared wavelengths (λc = 1.04, 1.24, 1.62, 2.18, and 3.78 μm) of the young variable star CQ Tau, aiming to constrain presence companions protoplanetary disc. reached a Ks-band contrast 14 mag with SPHERE/IRDIS at separations greater than 0${_{.}^{\prime\prime}}$4 from star. Our mass sensitivity curve rules out giant planets above 4 MJup immediately outside spiral arms ∼60 au 2–3 beyond 100 5σ confidence assuming hot-start models. do, however, detect four arms, double-arc evidence for shadows scattered light cast by misaligned inner observations may be explained an unseen close-in companion on inclined eccentric orbit. Such hypothesis would also account disc CO cavity disturbed kinematics.