Planetary-like spirals caused by moving shadows in transition discs

Abstract

Shadows and spirals seem to be common features of transition discs. Among the spiral-triggering mechanisms proposed, only one establishes a causal link between shadows and spirals so far. In fact, provided the presence of shadows in the disc, the combined effect of temperature gradient and differential disc rotation, creates strong azimuthal pressure gradients. After several thousand years, grand-design spirals develop in the gas phase. Previous works have only considered static shadows caused by an inclined inner disc. However, in some cases, the inner regions of circumbinary discs can break and precess. Thus, it is more realistic to consider moving shadow patterns in the disc. In this configuration, the intersection between the inner and the outer discs defines the line of nodes at which the shadows are cast. Here, we consider moving shadows and study the resulting circumbinary disc structure. We find that only static and prograde shadows trigger spirals, in contrast to retrograde ones. Interestingly, if a region of the disc corotates with the shadow, a planet-like signature develops at the co-rotation position. The resulting spirals resemble those caused by a planet embedded in the disc, with similar pitch angles.

6 pages, 4 figures. Accepted for publication in MNRAS letters

References in corpus (12)

• Astrophysics Source Code Library
• Spiral Density Waves in a Young Protoplanetary Disk
• Asymmetric features in the protoplanetary disk MWC758
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Shadows and spirals in the protoplanetary disk HD 100453
• Type I planetary migration in a self-gravitating disk
• Signatures of broken protoplanetary discs in scattered light and in sub-millimetre observations
• Spiral arms in the disk of HD 142527 from CO emission lines with ALMA
• Tearing up a misaligned accretion disc with a binary companion
• Variable dynamics in the inner disk of HD 135344B revealed with multi-epoch scattered light imaging
• HD 169142 in the eyes of ZIMPOL/SPHERE
• Spirals in protoplanetary disks from photon travel time

Cited by in corpus (5)

• The Disk Substructures at High Angular Resolution Project (DSHARP): III. Spiral Structures in the Millimeter Continuum of the Elias 27, IM Lup, and WaOph 6 Disks
• Flybys in protoplanetary discs: II. Observational signatures
• ALMA study of the HD 100453 AB system and the tidal interaction of the companion with the disk
• Near-Infrared Imaging of a Spiral in the CQ Tau Disk
• A Tight Relation between Spiral Arm Pitch Angle and Protoplanetary Disk Mass