TY - JOUR
T1 - Tidal Truncation of Circumplanetary Disks Fails above a Critical Disk Aspect Ratio
AU - Martin, Rebecca G.
AU - Armitage, Philip J.
AU - Lubow, Stephen H.
AU - Price, Daniel J.
N1 - Funding Information:
We thank anonymous referees for useful comments. Computer support was provided by UNLV’s National Supercomputing Center. R.G.M. and S.H.L. acknowledge support from NASA through grants 80NSSC21K0395 and 80NSSC19K0443. P.J.A. and R.G.M. acknowledge support from NASA TCAN award 80NSSC19K0639. We acknowledge the use of SPLASH (Price 2007) for the rendering of Figure 2. The paper arose from our mutual interaction at the Kavli Institute for Theoretical Physics program on “Bridging the Gap: Accretion and Orbital Evolution in Stellar and black hole Binaries,” funded by the National Science Foundation under grant No. NSF PHY-1748958. S.H.L. thanks the Simons Foundation for support of a visit to the Flatiron Institute.
Funding Information:
We thank anonymous referees for useful comments. Computer support was provided by UNLV’s National Supercomputing Center. R.G.M. and S.H.L. acknowledge support from NASA through grants 80NSSC21K0395 and 80NSSC19K0443. P.J.A. and R.G.M. acknowledge support from NASA TCAN award 80NSSC19K0639. We acknowledge the use of SPLASH (Price ) for the rendering of Figure . The paper arose from our mutual interaction at the Kavli Institute for Theoretical Physics program on “Bridging the Gap: Accretion and Orbital Evolution in Stellar and black hole Binaries,” funded by the National Science Foundation under grant No. NSF PHY-1748958. S.H.L. thanks the Simons Foundation for support of a visit to the Flatiron Institute.
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/8/1
Y1 - 2023/8/1
N2 - We use numerical simulations of circumplanetary disks to determine the boundary between disks that are radially truncated by the tidal potential and those where gas escapes the Hill sphere. We consider a model problem, in which a coplanar circumplanetary disk is resupplied with gas at an injection radius smaller than the Hill radius. We evolve the disk using the Phantom smoothed particle hydrodynamics code until a steady state is reached. We find that the most significant dependence of the truncation boundary is on the disk aspect ratio H/R. Circumplanetary disks are efficiently truncated for H/R ≲ 0.2. For H/R ≃ 0.3, up to about half of the injected mass, depending on the injection radius, flows outward through the decretion disk and escapes. As expected from analytic arguments, the conditions (H/R and Shakura-Sunyaev α) required for tidal truncation are independent of planet mass. A simulation with larger α = 0.1 shows stronger outflow than one with α = 0.01, but the dependence on transport efficiency is less important than variations of H/R. Our results suggest two distinct classes of circumplanetary disks: tidally truncated thin disks with dust-poor outer regions, and thicker actively decreting disks with enhanced dust-to-gas ratios. Applying our results to the PDS 70 c system, we predict a largely truncated circumplanetary disk, but it is possible that enough mass escapes to support an outward flow of dust that could explain the observed disk size.
AB - We use numerical simulations of circumplanetary disks to determine the boundary between disks that are radially truncated by the tidal potential and those where gas escapes the Hill sphere. We consider a model problem, in which a coplanar circumplanetary disk is resupplied with gas at an injection radius smaller than the Hill radius. We evolve the disk using the Phantom smoothed particle hydrodynamics code until a steady state is reached. We find that the most significant dependence of the truncation boundary is on the disk aspect ratio H/R. Circumplanetary disks are efficiently truncated for H/R ≲ 0.2. For H/R ≃ 0.3, up to about half of the injected mass, depending on the injection radius, flows outward through the decretion disk and escapes. As expected from analytic arguments, the conditions (H/R and Shakura-Sunyaev α) required for tidal truncation are independent of planet mass. A simulation with larger α = 0.1 shows stronger outflow than one with α = 0.01, but the dependence on transport efficiency is less important than variations of H/R. Our results suggest two distinct classes of circumplanetary disks: tidally truncated thin disks with dust-poor outer regions, and thicker actively decreting disks with enhanced dust-to-gas ratios. Applying our results to the PDS 70 c system, we predict a largely truncated circumplanetary disk, but it is possible that enough mass escapes to support an outward flow of dust that could explain the observed disk size.
UR - http://www.scopus.com/inward/record.url?scp=85166530470&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ace345
DO - 10.3847/1538-4357/ace345
M3 - Article
AN - SCOPUS:85166530470
SN - 0004-637X
VL - 953
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 1
M1 - 2
ER -