Abstract
The authors present the high-resolution soft X-ray spectrum in the range 50 - 350 Å of the hot DA white dwarf HZ 43, obtained with the 500 lines mm<SUP>-1</SUP> grating spectrometer on EXOSAT. Most remarkably, the spectrum indicates that the photosphere of HZ 43 consists solely of hydrogen, to a high degree of purity. Using a grid of hot, high-gravity LTE model atmospheres, the authors derive accurate atmospheric parameters for HZ 43 as well as constraints on the radius and luminosity of the white dwarf and on the column density of absorbing interstellar material. The effective temperature is T<SUB>eff</SUB> = 59,000 - 62,000K, and the fractional number density of helium in the photosphere is n(He)/n(H) ≤ 6×10<SUP>-6</SUP>.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.