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The onset of Wolf-Rayet wind outflow and the nature of the hot component in the symbiotic nova PU VulpeculaWe have analyzed temporal variations in the far ultraviolet He II (1640), Si IV (1393, 1402), and C IV (1548, 1550) line profiles in eight high dispersion, International Ultraviolet Explorer Short Wavelength Prime spectra of the symbiotic nova PU Vul by comparatively examining these profiles on a common velocity scale. We see clear evidence of the onset of a Wolf-Rayet-like wind outflow from the bloated, contracting white dwarf hot component with terminal velocity of approximately equals -550 to -600 km/s. We have quantitatively analyzed the complicated He II (1640) emission region for the first time and show that the discrete absorption features seen in the He II region occur at precisely the same velocites in each spectrum, thus demonstrating that the absorbing source is steady and not affected by any orbital motion. We demonstrate that there is an underlying He II wind emission feature whose true shape is hidden by superposed absorption due to the foreground red giant wind flowing in front of the white dwarf and abscuring the white dwarf's wind outflow. We present synthetic spectra of He II emission behind an absorbing slab with u = 20 km/s, T = 5000 K, and column densities in the range N = 1 x 10(exp 22) and 1 x 10(exp 23)/sq cm which explain these absorptions. Our analysis of the Si IV and C IV resonance doublets, in velocity space, reveal temporal variations in the profile between 1987 and 1991 with the emergence of clear P Cygni profiles in Si IV by 1990. A nebular emission feature in C III 1909 also appears in the most recent spectra (e.g., SW42538H) while it was absent or extremely weak in the earliest spectra (e.g., SW36332H), thus strengthening evidence that the nebular emission, as seen in permitted and semiforbidden lines, intensities in step with the onset of the hot, fast, wind outflow. We also report the first detection of narrow interstellar (circumbinary shell?) absorption lines near -1 km/s, most strongly in Al III (1854, 1862) and Si IV (1392, 1402). We have carried out a rough quantitative analysis of the He II wind emission by using the theoretical He II Wolf-Rayet profiles of Hamann & Schmutz (1987). We obtain a lower limit to the He II net emission equivalent width of approximately 1 A, a hot component temperature in the range 25,000 to 35,000 K, a hot component radius in the range 5 solar radius to 30 solar radius, a maximum wind velocity of approximately equals -600 km/s and a rough upper limit to the mass-loss rate of less than 1 x 10(exp -5) solar mass/yr. To our knowledge, this is the first quantitative wind analysis, albeit crude, to be carried out for the hot component of a symbiotic nova or symbiotic variable.
Document ID
19950044772
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sion, Edward M.
(Villanova University Villanova, PA, United States)
Shore, Steven N.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ready, Christian J.
(Villanova University Villanova, PA, United States)
Scheible, Maureen P.
(Villanova University Villanova, PA, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1993
Publication Information
Publication: Astronomical Journal
Volume: 106
Issue: 5
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
95A76371
Funding Number(s)
CONTRACT_GRANT: NSF AST-90-16283
CONTRACT_GRANT: NAG5-343
Distribution Limits
Public
Copyright
Other

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