  The Galactic hard X-ray transient SWIFT J195509+261406 was first observed as
a gamma-ray burst GRB 070610. Within 3 days after the burst, more than forty
optical flares had been observed. Here we propose that this peculiar event
should be associated with a white dwarf. The hard X-ray burst itself may be
triggered by the collision between two planets orbiting the white dwarf. Some
cracked frag-ments produced in the collision then fall onto the surface of the
white dwarf in several days, giving birth to the observed optical flares via
cyclotron radiation. Our model can satisfactorily explain the basic features of
the observations.
