Gap Clearing by Planets in a Collisional Debris Disk

Abstract

We apply our 3D debris disk model, SMACK, to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power ($\alpha$=2/7). We find that the gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index alpha of the power law depends on the age of the system t relative to the collisional timescale $t_{coll}$ of the disk by $\alpha =0.32(t/t_{coll}{)}^{-0.04}$, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between the collisions and the mean motion resonances near the chaotic zone. We investigate the effects of the initial eccentricity distribution of the disk particles and find a negligible effect on the gap size at Jovian planet masses, since collisions tend to erase memory of the initial particle eccentricity distributions. Finally, we find that the presence of Trojan analogs is a potentially powerful diagnostic of planets in the mass range ~1-10 $M_{jup}$. We apply our model to place new upper limits on planets around Fomalhaut, HR 4796 A, HD 202628, HD 181327, and $\beta$ Pictoris.

11 pages, 8 figures, Accepted for publication in ApJ

References in corpus (7)

• Optical Images of an Exosolar Planet 25 Light Years from Earth
• Molecular Gas Clumps from the Destruction of Icy Bodies in the $\beta$ Pictoris Debris Disk
• STIS Imaging of the HR 4796A Circumstellar Debris Ring
• Discovery of an 86 AU Radius Debris Ring Around HD 181327
• Revealing Asymmetries in the HD 181327 Debris Disk: A Recent Massive Collision or ISM Warping
• On the observability of resonant structures in planetesimal disks due to planetary migration
• Planets of Beta Pictoris revisited

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• The unseen planets of double belt debris disk systems
• Subaru/SCExAO First-Light Direct Imaging of a Young Debris Disk around HD 36546
• HD 106906: A Case Study for External Perturbations of a Debris Disk
• Disk Detective: Discovery of New Circumstellar Disk Candidates through Citizen Science
• Numerical search for a potential planet sculpting the young disc of HD 115600