We present HST spectroscopy and imaging , along with new ground-based spectroscopy and ROSAT HRI imaging , of the He II emitting nebula N44C and its ionizing star .
A GHRS spectrogram of the ionizing star yields a spectral type of about O7 for the star .
The lack of P Cygni profiles for Si IV and C IV indicates that the star is not a supergiant .
The nebular abundances in the ionized gas are consistent with average abundances for LMC H II regions , with the possible exception that nitrogen may be enhanced .
Enrichment by a former evolved companion star is not evident .
A long-slit echelle spectrogram in H \alpha + [ N II ] shows no evidence for high-velocity gas in N44C .
This rules out high-velocity shocks as the source of the nebular He II emission .
A 108 ks ROSAT HRI image of N44C shows no X-ray point source to a 3 \sigma upper limit L _ { X } < 10 ^ { 34 } erg s ^ { -1 } in the 0.1-2.0 keV band .
Based on new measurements of the electron density in the He II emitting region , we derive recombination timescales of \approx 20 yrs for He ^ { +2 } and \approx 4 yrs for Ne ^ { +4 } .
If N44C is a fossil X-ray ionized nebula , this places severe constraints on when the putative X-ray source could have turned off .
The presence of strong [ Ne IV ] emission in the nebula is puzzling if the ionizing source has turned off .
It is possible the system is related to the Be X-ray binaries , although the O star in N44C does not show Be characteristics at the present time .
Monitoring of X-rays and He II emission from the nebula , as well as a radial velocity study of the ionizing star , are needed to fully understand the emission line spectrum of N44C .