Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption

Post-main-sequence planetary science has been galvanized by the striking variability, depth and shape of the photometric transit curves due to objects orbiting white dwarf WD 1145+017, a star which also hosts a dusty debris disc and circumstellar gas, and displays strong metal atmospheric pollution....

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2017-02, Vol.465 (1), p.1008-1008
Main Authors: Veras, Dimitri, Carter, Philip J, Leinhardt, Zoee M, Gaensicke, Boris T
Format: Article
Language:English
Subjects:
Asteroids
Astronomy
Bulk density
Computer simulation
Density
Disruption
Eccentricity
Mathematical models
Photometry
Physical properties
Simulation
Tides
Variables
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Summary:Post-main-sequence planetary science has been galvanized by the striking variability, depth and shape of the photometric transit curves due to objects orbiting white dwarf WD 1145+017, a star which also hosts a dusty debris disc and circumstellar gas, and displays strong metal atmospheric pollution. However, the physical properties of the likely asteroid which is discharging disintegrating fragments remain largely unconstrained from the observations. This process has not yet been modelled numerically. Here, we use the N-body code pkdgrav to compute dissipation properties for asteroids of different spins, densities, masses and eccentricities. We simulate both homogeneous and differentiated asteroids, for up to 2 yr, and find that the disruption time-scale is strongly dependent on density and eccentricity, but weakly dependent on mass and spin. We find that primarily rocky differentiated bodies with moderate (~3-4 g cm super( -3)) bulk densities on near-circular (e ... 0.1) orbits can remain intact while occasionally shedding mass from their mantles. These results suggest that the asteroid orbiting WD 1145+017 is differentiated, resides just outside of the Roche radius for bulk density but just inside the Roche radius for mantle density, and is more akin physically to an asteroid like Vesta instead of one like Itokawa. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stw2748