  Ultraviolet imaging of the remnant of Supernova 1885 in M31 with the Hubble
Space Telescope using the F255W filter on the WFPC2 reveals a dark spot of Fe
II absorption at the remnant's known position in the bulge of M31. The diameter
of the absorbing spot is 0"55 +- 0"15, slightly smaller than, but consistent
with, the 0"70 +- 0"05 diameter measured in the higher quality WFPC2 Ca II
absorption image previously reported by us. The measured ratio of flux inside
to outside SNR 1885 in the Fe II image is 0.24 +- 0.17, consistent with the
ratio 0.33 +- 0.04 expected on the basis of a model fit to the previously
obtained near-UV FOS spectrum. The observed depth of Fe II absorption suggests
that Fe II is fully saturated, with an iron mass in the range M_Fe = 0.1-1.0
Msun. Besides Fe, ion species Mg I, Mg II, and Mn I probably make some
contribution to the absorption from the SN 1885 remnant in the F255W image.

Astrophysics