EVIDENCE FOR GAS FROM A DISINTEGRATING EXTRASOLAR ASTEROID

We report high-resolution spectroscopic observations of WD 1145+017-a white dwarf that was recently found to be transitted by multiple asteroid-sized objects within its tidal radius. We discovered numerous circumstellar absorption lines with linewidths of ~300 km s super(-1) from Mg, Ca, Ti, Cr, Mn, Fe, and Ni, possibly from several gas streams produced by collisions among the actively disintegrating objects. The atmosphere of WD 1145+017 is polluted with 11 heavy elements, including O, Mg, Al, Si, Ca, Ti, V:, Cr, Mn, Fe, and Ni. Evidently, we are witnessing the active disintegration and subsequent accretion of an extrasolar asteroid.