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

Iain Hammond , Valentin Christiaens , Daniel J. Price , Maria Giulia Ubeira-Gabellini , Jennifer Baird , Josh Calcino , Myriam Benisty (1) , Giuseppe Lodato , Leonardo Testi , Christophe Pinte (1) , Claudia Toci , Davide Fedele

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

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

Mots clés: techniques: image processing; planet-disc interactions; protoplanetary discs; Astrophysics - Earth and Planetary Astrophysics

Domaines: Planète et Univers [physics]

Iain Hammond, Valentin Christiaens, Daniel J. Price, Maria Giulia Ubeira-Gabellini, Jennifer Baird, et al.. External or internal companion exciting the spiral arms in CQ Tau?. Monthly Notices of the Royal Astronomical Society, 2022, 515, pp.6109-6121. ⟨10.1093/mnras/stac2119⟩. ⟨insu-03860276⟩