1999A&A...352..287B

In ORFEUS II spectra of the sdO star BD +39 3226 interstellar hydrogen and deuterium is detected. >From Ly α profile fitting and a curve of growth analysis of the Lyman series of HI and DI we derive the column densities N_H=1.20^+0.28_–0.22.10²⁰cm^–2 and N_D=1.45^+0.50_–0.38.10¹⁵cm^–2. From the analysis of metal absorption lines in ORFEUS and IUE spectra we obtain column densities for 11 elements. In addition, we examine absorption lines of H₂ for rotational excitation states up to J=7. We find an H₂ ortho-to-para ratio of 2.5, the fractional abundance of molecular hydrogen has a low value of logf=-4.08 for a total amount of N(H₂)=4.8^+2.0_–1.6.10¹⁵cm^–2. The column densities of the excitation states reveal a moderate Boltzmann excitation temperature of 130K and an equivalent excitation temperature for the excited upper states due to UV pumping of <1800K.