A Gap-sharing Planet Pair Shaping the Crescent in HD 163296: A Disk Sculpted by a Resonant Chain
Abstract
The Atacama Large Millimeter Array observations of the disk around HD 163296 have resolved a crescent-shape substructure at around 55 au, inside and off-center from a gap in the dust that extends from 38 to 62 au. In this work we propose that both the crescent and the dust rings are caused by a compact pair (period ratio ≃4:3) of sub-Saturn-mass planets inside the gap, with the crescent corresponding to dust trapped at the L 5 Lagrange point of the outer planet. This interpretation also reproduces well the gap in the gas recently measured from the CO observations, which is shallower than what is expected in a model where the gap is carved by a single planet. Building on previous works arguing for outer planets at ≈86 and ≈137 au, we provide a global model of the disk that best reproduces the data and shows that all four planets may fall into a long resonant chain, with the outer three planets in a 1:2:4 Laplace resonance. We show that this configuration is not only an expected outcome from disk-planet interaction in this system, but it can also help constrain the radial and angular position of the planet candidates using three-body resonances.
- Publication:
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The Astrophysical Journal
- Pub Date:
- March 2023
- DOI:
- 10.3847/2041-8213/acbea8
- arXiv:
- arXiv:2301.13260
- Bibcode:
- 2023ApJ...945L..37G
- Keywords:
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- Protoplanetary disks;
- Planet formation;
- Radiative transfer simulations;
- Hydrodynamical simulations;
- Planetary dynamics;
- Dust continuum emission;
- Planetary system evolution;
- Planetary-disk interactions;
- 1300;
- 1241;
- 1967;
- 767;
- 2173;
- 412;
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- 2204;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 11 pages, 8 figures, re-submitted to ApJL, comments welcome