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The early spectral evolution of Nova Cassiopeiae 1993In this paper we describe the evolution of Nova Cas 1993 over the first two months of its outburst. We present an ultraviolet light curve that covers the period from announcement to just after dust began forming in the ejecta (1994 Feb. 15) and International Ultraviolet Explorer (IUE) spacecraft constraints forced us to halt our observations. We have used spherical, expanding, Non-local Thermodynamic Equilibrium (NLTE) stellar atmospheres to compute synthetic spectra and have compared the results to combined ultraviolet (low-resolution 1200-3400 A and high-resolution 2400-3300 A) spectra. Our fits show that the effective temperature of the ejecta increased from approx. 8000 to about approx. 16 000 K between 1993 Dec. 12 and 1993 Dec. 26. The temperature then increased more slowly to approx. 24 000 on 1994 Jan. 28. A preliminary abundance analysis shows evidence for hydrogen depletion, as we also found for Nova V1974 Cygni; however we find a larger enhancement of carbon, nitrogen, and oxygen. We also show that the principal mechanism for mass ejection in this nova is a radiation pressure driven wind and that mechanical driving is not necessary.
Document ID
19950033247
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hauschildt, Peter H.
(Arizona State Univ. Tempe, AZ, United States)
Starrfield, Sumner
(Arizona State Univ. Tempe, AZ, United States)
Shore, Steven N.
(Indiana Univ. South Bend, South Bend, IN, United States)
Gonzalez-Riestra, Rosario
(IUE Observatory Villafranca, Spain)
Sonneborn, George
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Allard, France
(Univ. of British Columbia, Vancouver, BC United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1994
Publication Information
Publication: The Astronomical Journal
Volume: 108
Issue: 3
ISSN: 0004-6256
Subject Category
Astronomy
Accession Number
95A64846
Funding Number(s)
CONTRACT_GRANT: NSF AST-91-14917
CONTRACT_GRANT: NAGW-2628
Distribution Limits
Public
Copyright
Other

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