Are the spiral arms in the MWC 758 protoplanetary disc driven by a companion inside the cavity?

Josh Calcino , Valentin Christiaens , Daniel J. Price , Christophe Pinte , Tamara M. Davis , Nienke van der Marel , Nicolás Cuello (1)

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

Spiral arms in protoplanetary discs are thought to be linked to the presence of companions. We test the hypothesis that the double spiral arm morphology observed in the transition disc MWC 758 can be generated by an ≍10M_Jup companion on an eccentric orbit internal to the spiral arms. Previous studies on MWC 758 have assumed an external companion. We compare simulated observations from three-dimensional hydrodynamics simulations of disc-companion interaction to scattered light, infrared and CO molecular line observations, taking into account observational biases. The inner companion hypothesis is found to explain the double spiral arms, as well as several additional features seen in MWC 758 - the arc in the north-west, substructures inside the spiral arms, the cavity in CO isotopologues, and the twist in the kinematics. Testable predictions include detection of fainter spiral structure, detection of a point source south-southeast of the primary, and proper motion of the spiral arms.

Mots clés: hydrodynamics; planet-disc interactions; protoplanetary discs; circumstellar matter; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics

Domaines: Planète et Univers [physics]

Josh Calcino, Valentin Christiaens, Daniel J. Price, Christophe Pinte, Tamara M. Davis, et al.. Are the spiral arms in the MWC 758 protoplanetary disc driven by a companion inside the cavity?. Monthly Notices of the Royal Astronomical Society, 2020, 498, pp.639-650. ⟨10.1093/mnras/staa2468⟩. ⟨insu-03705174⟩