Numerical Simulations of Gaseous Disks Generated from Collisional Cascades at the Roche Limits of White Dwarf Stars

Abstract

We consider the long-term evolution of gaseous disks fed by the vaporization of small particles produced in a collisional cascade inside the Roche limit of a 0.6 Msun white dwarf. Adding solids with radius \r0\ at a constant rate ${\dot{M}}_0$ into a narrow annulus leads to two distinct types of evolution. When ${\dot{M}}_0>{\dot{M}}_{0,crit}$ = $3\times 10^4(r_0/1\mathrm{km}{)}^{3.92}$~g s${}^{-1}$, the cascade generates a fairly steady accretion disk where the mass transfer rate of gas onto the white dwarf is roughly ${\dot{M}}_0$ and the mass in gas is $M_g\approx 2.3\times 10^{22}({\dot{M}}_0/10^{10}g{s}^{-1})(1500\mathrm{K}/T_0)(10^{-3}/\alpha )$~g, where $T_0$ is the temperature of the gas near the Roche limit and $\alpha$ is the dimensionless viscosity parameter. If ${\dot{M}}_0<{\dot{M}}_{0,crit}$, the system alternates between high states with large mass transfer rates and low states with negligible accretion. Although either mode of evolution adds significant amounts of metals to the white dwarf photosphere, none of our calculations yield a vertically thin ensemble of solids inside the Roche limit. X-ray observations can place limits on the mass transfer rate and test this model for metallic line white dwarfs.

30 pages and 8 figures, ApJ, accepted

References in corpus (36)

• Accretion disc viscosity: how big is alpha?
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• The frequency of planetary debris around young white dwarfs
• Toward a Deterministic Model of Planetary Formation V. Accumulation Near the Ice Line
• A gaseous metal disk around a white dwarf
• Pollution of single white dwarfs by accretion of many small asteroids
• Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 Solar Mass Main Sequence Stars
• Formation of planetary debris discs around white dwarfs I: Tidal disruption of an extremely eccentric asteroid
• Externally-polluted white dwarfs with dust disks
• The frequency and infrared brightness of circumstellar discs at white dwarfs
• The Chemical Composition of an Extrasolar Kuiper-Belt-Object
• The accretion-diffusion scenario for metals in cool white dwarfs
• SDSSJ104341.53+085558.2: A second white dwarf with a gaseous debris disc
• The chemical diversity of exo-terrestrial planetary debris around white dwarfs
• Infrared Emission from the Dusty Disk Orbiting GD 362, An Externally-Polluted White Dwarf
• Detectable close-in planets around white dwarfs through late unpacking
• Signs of a faint disc population at polluted white dwarfs
• Variable Emission from a Gaseous Disc around a Metal-Polluted White Dwarf
• Hydrogen delivery onto white dwarfs from remnant exo-Oort cloud comets
• Planetary engulfment as a trigger for white dwarf pollution
• Numerical Simulations of Collisional Cascades at the Roche Limits of White Dwarf Stars
• Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption
• The viscosity parameter alpha and the properties of accretion disc outbursts in close binaries
• The orbital evolution of asteroids, pebbles and planets from giant branch stellar radiation and winds
• White dwarf pollution by planets in stellar binaries
• Does a Differentiated, Carbonate-Rich, Rocky Object Pollute the White Dwarf SDSSJ104341.53+085558.2?
• Kepler and the seven dwarfs: detection of low-level day-timescale periodic photometric variations in white dwarfs
• The Fate of Exomoons in White Dwarf Planetary Systems
• Another one grinds the dust: Variability of the planetary debris disc at the white dwarf SDSS J104341.53+085558.2
• Formation of Super-Earth Mass Planets at 125-250 AU from a Solar-type Star
• Linking long-term planetary $N$-body simulations with periodic orbits: application to white dwarf pollution
• Infrared Photometric Analysis of White Dwarfs from The Two Micron All Sky Survey and the Spitzer Space Telescope
• Rocky Planet Formation: Quick and Neat
• Post main sequence evolution of icy minor planets II: water retention and white dwarf pollution around massive progenitor stars
• Magnetospherically-trapped dust and a possible model for the unusual transits at WD 1145+017
• The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures

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