2003/01/29 by K. E. Belle, Kunegunda E. Belle, Steve B. Howell +6 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/368180
published as Astrophys.J. 587 (2003) 373-383 · Accepted to ApJ, 28 pages including 12 figures
arxiv created 2003/01/29 · openalex publication_date 2003/04/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present the results of our analysis of six orbits of Hubble Space Telescope Space Telescope Imaging Spectrograph ( HST /STIS) time-tagged spectroscopy of the intermediate polar, EX Hydrae. The high time and wavelength resolution of the HST /STIS spectra provided an excellent opportunity to study the UV properties of EX Hya. Measurements of the continuum and emission-line fluxes corroborate earlier studies that show that the emission-line fluxes are modulated more strongly than the continuum flux and originate from the accretion curtains, while the continuum flux originates from the white dwarf photosphere. The measured K amplitude of the narrow emission-line radial velocity curve is used to calculate a white dwarf mass of 0.91 ± 0.05 M ☉ . Synthetic white dwarf photosphere and accretion disk spectral models are used to further refine the white dwarf and accretion disk properties. Using the spectral models, it is determined that EX Hya has a white dwarf of mass 0.9 M ☉ , T = 23,000 K, and an accretion disk truncated at 2.5 R WD and is at a distance of 60 pc.