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Symbiotic starsThe physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.
Document ID
19840055586
Document Type
Reprint (Version printed in journal)
Authors
Kafatos, M. (George Mason University Fairfax, VA, United States)
Michalitsianos, A. G. (NASA Goddard Space Flight Center Laboratory for Astronomy and Solar Physics, Greenbelt, MD, United States)
Date Acquired
August 12, 2013
Publication Date
July 1, 1984
Publication Information
Publication: Scientific American
Volume: 251
ISSN: 0036-8733
Subject Category
ASTROPHYSICS
Distribution Limits
Public
Copyright
Other