S. Mereghetti et al., ON THE NATURE OF THE X-RAY-EMISSION FROM 1E-1024.0-5732 WACK-2134 - THE 1ST X-RAY-SELECTED WOLF-RAYET STAR/, The Astrophysical journal, 424(2), 1994, pp. 943-946
We report on a ROSAT PSPC observation of the X-ray source 1E 1024.0-57
32. The optical identification with the emission-line star Wackerling
2134 is confirmed, but we do not find any evidence of the periodic pul
sations at 61 ms which were previously reported in its X-ray flux. On
the basis of the new timing and spectral results, a reexamination of t
he old X-ray and optical data, and a new optical spectrum, we propose
that this source is a new Wolf-Rayet star of type WN6. The high level
of X-ray emission hints at the presence of a binary companion to Wack
2134. This could be either an accreting compact object or a massive OB
star, in which case the X-rays would be produced in the colliding win
ds of the two stars. The small equivalent widths of the Wolf-Rayet sta
r emission lines strongly support the 0-star companion hypothesis. If
this scenario is confirmed, Wack 2134 would be the first case of an X-
ray-selected Wolf-Rayet star.