Transient outburst events from tidally disrupted asteroids near white   dwarfs
  We discuss the possibility of observing the transient formation event of an accretion disk from the tidal destruction process of an asteroid near a white dwarf (WD). This scenario is commonly proposed as the explanation for dusty disks around WDs. We find that the initial formation phase lasts for about a month and material that ends in a close orbit near the WD forms a gaseous disk rather than a dusty disk. The mass and size of this gaseous accretion disk is very similar to that of Dwarf Novae (DNe) in quiescence. The bolometric luminosity of the event at maximum is estimated to be 0.001-0.1Lsun. Based on the similarity with DNe we expect that transient outburst events such as discussed here will be observed at wavelengths ranging from visible to the X-ray, and be detected by present and future surveys. 
Ealeal Bear and Noam Soker (Technion, Israel)
astro-ph.SR