Spectral behavior of the symbiotic nova AG Pegasi observed with IUE and HST |
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| Institution: | 1. National Research Institute of Astronomy and Geophysics, Astronomy Department, Helwan, Cairo, Egypt;2. Delaware State University, Dover, DE, USA;1. Astronomy Dept., National Research Institute of Astronomy and Geophysics, (NRIAG), 11421, Box:138, Helwan, Cairo, Egypt.;2. Kottamia Center of Scientific Excellence in Astronomy and Space Sciences (KCScE) STDF, ASRT, Cairo, Egypt;1. Research Institute for Astronomy and Astrophysics of Maragha, Maragha, Iran;2. RIAAM Observatory, Research Institute for Astronomy and Astrophysics of Maragha, Maragha, Iran;1. Astronomy Department, Faculty of Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia;2. Sousse University, ESSTHS, Lamine Abbassi Street, H. Sousse 4011, Tunisia |
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| Abstract: | Ultraviolet spectra from the International Ultraviolet Explorer (IUE) and from the Hubble Space Telescope (HST) of the symbiotic novae AG Peg during the period 1978–1996 are analyzed. Some spectra showing the modulations of spectral lines at different times are presented. We determined the reddening from the 2200 Å feature, finding that E(B?V) = 0.10 ± 0.02. We studied N IV] at 1486 Å, C IV 1550 Å, and O III] at 1660 Å, produced in the fast wind from the hot white dwarf. The mean wind velocity of the three emission lines is 1300 km s?1 (FWHM). The mean wind mass loss rate is ～6 × 10?7 M⊙ yr?1. The mean temperature is ～6.5 × 105 K. The mean ultraviolet luminosity is ～5 × 1033 erg s?1. The modulations of line fluxes in the emitting region at different times are attributed to the variations of density and temperature of the ejected matter as a result of variations in the rate of mass loss. |
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