Post-main-sequence planetary science has been galvanised 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 two years , and find that the disruption timescale is strongly dependent on density and eccentricity , but weakly dependent on mass and spin .
We find that primarily rocky differentiated bodies with moderate ( \sim 3 - 4 g/cm ^ { 3 } ) bulk densities on near-circular ( e \lesssim 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 .