How empty are disk gaps opened by giant planets?

Journal Article · Thu Feb 20 04:00:00 EST 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/782/2/88· OSTI ID:22351425

Fung, Jeffrey ^[1]; Shi, Ji-Ming; Chiang, Eugene ^[2]

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1. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada)
2. Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States)

Gap clearing by giant planets has been proposed to explain the optically thin cavities observed in many protoplanetary disks. How much material remains in the gap determines not only how detectable young planets are in their birth environments, but also how strong co-rotation torques are, which impacts how planets can survive fast orbital migration. We determine numerically how the average surface density inside the gap, Σ{sub gap}, depends on planet-to-star mass ratio q, Shakura-Sunyaev viscosity parameter α, and disk height-to-radius aspect ratio h/r. Our results are derived from our new graphics processing unit accelerated Lagrangian hydrodynamical code PEnGUIn and are verified by independent simulations with ZEUS90. For Jupiter-like planets, we find Σ{sub gap}∝q {sup –2.2}α{sup 1.4}(h/r){sup 6.6}, and for near brown dwarf masses, Σ{sub gap}∝q {sup –1}α{sup 1.3}(h/r){sup 6.1}. Surface density contrasts inside and outside gaps can be as large as 10{sup 4}, even when the planet does not accrete. We derive a simple analytic scaling, Σ{sub gap}∝q {sup –2}α{sup 1}(h/r){sup 5}, that compares reasonably well to empirical results, especially at low Neptune-like masses, and use discrepancies to highlight areas for progress.

• OSTI ID: 22351425
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 782; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ASPECT RATIO
DENSITY
INTERACTIONS
JUPITER PLANET
LAGRANGIAN FUNCTION
MASS
NEPTUNE PLANET
PROTOPLANETS
ROTATION
SATELLITES
SCALING
SIMULATION
STARS
SURFACES
VISCOSITY