Time-resolved ultraviolet and optical spectroscopy of the pulsating X-ray source H 2252-035.

Abstract

Simultaneous ultraviolet and optical spectral measurements of the pulsating X-ray source H2252-035 have been made about its 3.6 hr binary orbital cycle with a time resolution of 30-70 minutes. A 2200 Å feature in the continous spectral distribution of the object suggests an amount of reddening corresponding to E(B-V) = 0.10 with 3 σ upper and lower bounds of 0.14 and 0.02. A two-component spectrum consisting of a power law with a spectral index α = 2.74 and a blackbody with a temperature T = 1.34 × 10⁴K fits all the data on H2252-035 from 1200 to 22000 Å. The UV spectra exhibit emission lines of N V λ1240, Si IV λ1400, C IV λ1549, and Mg II λ2800. The emission line intensities are variable by about a factor of 2. Models for explaining these variations are briefly discussed.