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Evolution of the symbiotic binary system AG DranconisWe present an analysis of new and archival photometric and spectroscopic observations of the symbiotic star AG Draconis. This binary has undergone several 1 - 3 mag optical and ultraviolet eruptions during the past 15 years. Our combination of optical and ultraviolet spectroscopic data allow a more complete analysis of this system than in previous papers. AG Dra is composed of a K-type bright giant M(sub g) approximately 1.5 solar mass) and a hot, compact star M(sub h approximatelly 0.4 - 0.6 solar mass) embedded in a dense, low metallicity nebula. The hot component undergoes occasional thermonuclear runaways that produce 2 - 3 mag optical/ultraviolet eruptions. During these eruptions, the hot component develops a low velocity wind that quenches x-ray emission from the underlying hot white dwarf. The photoionized nebula changes its volume by a factor of 5 throughout an eruptin cycle. The K bright giant occults low ionization emission lines during superior conjunctions at all outburst phases but does not occult high ionization lines in outburst (and perhaps quiescence). This geometry and the component masses suggest a system inclination of i approximately 30 deg - 45 deg.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Mikolajewska, Joanna (Nicolaus Copernicus Astronomical Center Warsaw, Poland)
Kenyon, Scott J (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA United States)
Mikolajewski, Maciej (Nicolaus Copernicus University Torun, Poland)
Garcia, Michael R. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA United States)
Polidan, Ronald S. (NASAGoddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
March 1, 1995
Publication Information
Publication: Astronomical Journal
Volume: 109
Issue: 3
ISSN: 0004-6256
Subject Category
Funding Number(s)
Distribution Limits