Daniel J. Price, Nicolas Cuello, Christophe Pinte, Daniel Mentiplay, Simon Casassus, Valentin Christiaens, Grant M. Kennedy, Jorge Cuadra, Sebastian Perez M., Sebastian Marino, Philip J. Armitage, Alice Zurlo, Attila Juhasz, Enrico Ragusa, Guillaume Laibe and Giuseppe Lodato

PDF full text pdf, accepted to MNRAS 07 March 2018 (arXiv:1803.02484)


We present 3D hydrodynamical models of the HD142527 protoplanetary disc, a bright and well studied disc that shows spirals and shadows in scattered light around a 100 au gas cavity, a large horseshoe dust structure in mm continuum emission, together with mysterious fast radial flows and streamers seen in gas kinematics. By considering several possible orbits consistent with the observed arc, we show that all of the main observational features can be explained by one mechanism — the interaction between the disc and the observed binary companion. We find that the spirals, shadows and horseshoe are only produced in the correct position angles by a companion on an inclined and eccentric orbit approaching periastron — the `red' family from Lacour et al. (2016). Dust-gas simulations show radial and azimuthal concentration of dust around the cavity, consistent with the observed horseshoe. The success of this model in the HD142527 disc suggests other mm-bright transition discs showing cavities, spirals and dust asymmetries may also be explained by the interaction with central companions.

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Movies and images (c) 2018 Daniel Price, released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
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Simulations of HD142527 with different possible orbits for the binary

Orbit R1. This orbit produces the closest match to the spiral arms seen in HD142527. We also see the formation of a circumprimary disc in the correct orientation to explain the observed shadows on the outer disc.
Orbit R2. This orbit produces the best match with the observed cavity size in HD142527. Also, asymmetry around the cavity edge matches the position angle of the dust horseshoe seen with the ALMA telescope.
Orbit B1. The `blue' family of orbits (B1, B2, B3) have the secondary observed just past closest approach (periastron). However, they do not match the observed spiral pattern around the cavity edge
Orbit B2. Again, the spiral arms seen around the cavity does not match what is seen in the observations.
Orbit B3. Here the orientation of the inner disc is wrong compared to the observed shadows on the outer disc. However, all of our simulations show the same general features — spiral arms, a large cavity, a misaligned circumprimary disc and asymmetries in the gas distribution around the cavity edge
Orbit R1 shown once per orbital period, showing precession of overdensity around the edge of the cavity. This overdensity is reflected in the bright horseshoe seen in mm-emission with the ALMA telescope.