A White Dwarf Accreting Asteroids

We propose to observe the isolated white dwarf G2938 (D 14 pc) to search forXrays from the accretion of circumstellar material. Most white dwarfs haveatmospheres that are either pure H or He, but G2938 is rare in that it alsoexhibits atmospheric metal lines, even though metals should settle out of thephotosphere is only virgul20 years. G2938 also exhibits excess infrared emissionfrom orbiting dust that may have been produced by the tidal disruption of anasteroid. Accretion from this dust can account for the atmospheric metals. Weexpect between 3x10^25 and 8x10^27 erg/s in Xrays; the exact value wouldprovide the first measurement of the efficiency of Xray production at accretionrates orders of magnitudes below those detectable in CVs. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]