Dust traps in the protoplanetary disc MWC 758: two vortices produced by two giant planets?

Abstract

Resolved ALMA and VLA observations indicate the existence of two dust traps in the protoplanetary disc MWC 758. By means of 2D gas+dust hydrodynamical simulations post-processed with 3D dust radiative transfer calculations, we show that the spirals in scattered light, the eccentric, asymmetric ring and the crescent-shaped structure in the (sub)millimetre can all be caused by two giant planets: a 1.5-Jupiter mass planet at 35 au (inside the spirals) and a 5-Jupiter mass planet at 140 au (outside the spirals). The outer planet forms a dust-trapping vortex at the inner edge of its gap (at ~85 au), and the continuum emission of this dust trap reproduces the ALMA and VLA observations well. The outer planet triggers several spiral arms which are similar to those observed in polarised scattered light. The inner planet also forms a vortex at the outer edge of its gap (at ~50 au), but it decays faster than the vortex induced by the outer planet, as a result of the disc's turbulent viscosity. The vortex decay can explain the eccentric inner ring seen with ALMA as well as the low signal and larger azimuthal spread of this dust trap in VLA observations. Finding the thermal and kinematic signatures of both giant planets could verify the proposed scenario.

18 pages, 8 figures, accepted for publication in MNRAS

References in corpus (16)

• Asymmetric features in the protoplanetary disk MWC758
• On the corotation torque in a radiatively inefficient disk
• Type I planetary migration in a self-gravitating disk
• Standing on the shoulders of giants: Trojan Earths and vortex trapping in low mass self-gravitating protoplanetary disks of gas and solids
• Dust Trapping by Vortices in Transitional Disks: Evidence for Non-ideal MHD Effects in Protoplanetary Disks
• On the Stability of Elliptical Vortices in Accretion Discs
• Effects of dust feedback on vortices in protoplanetary disks
• Exploring dust around HD142527 down to 0.025" / 4au using SPHERE/ZIMPOL
• Dust-trapping vortices and a potentially planet-triggered spiral wake in the pre-transitional disk of V1247 Orionis
• Vortices and spirals in the HD135344B transition disk
• Long Term Evolution of Planet-Induced Vortices in Protoplanetary Disks
• Slowly-growing gap-opening planets trigger weaker vortices
• Rossby wave instability does not require sharp resistivity gradients
• Probing the cold dust emission in the AB Aur disk: a dust trap in a decaying vortex?
• Vortex stretching in self-gravitating protoplanetary discs
• Gap formation and stability in non-isothermal protoplanetary discs

Cited by in corpus (8)

• Dust unveils the formation of a mini-Neptune planet in a protoplanetary ring
• Spiral arms in the proto-planetary disc HD100453 detected with ALMA: evidence for binary-disc interaction and a vertical temperature gradient
• Annular substructures in the transition disks around LkCa 15 and J1610
• Are the spiral arms in the MWC 758 protoplanetary disc driven by a companion inside the cavity?
• Dynamical Evidence of a Spiral Arm--Driving Planet in the MWC 758 Protoplanetary Disk
• Intermittent planet migration and the formation of multiple dust rings and gaps in protoplanetary disks
• Dynamical signatures of Rossby vortices in cavity-hosting disks
• Constraints on a Putative Planet Sculpting the V4046 Sagittarii Circumbinary Disk