Symbiotic star

A symbiotic binary is a type of binary star system, often simply called a symbiotic star. They usually contain a white dwarf with a companion red giant. The cool giant star loses material via Roche lobe overflow or through its stellar wind, which flows onto the hot compact star, usually via an accretion disk. A symbiotic binary is a type of binary star system, often simply called a symbiotic star. They usually contain a white dwarf with a companion red giant. The cool giant star loses material via Roche lobe overflow or through its stellar wind, which flows onto the hot compact star, usually via an accretion disk. Symbiotic binaries are of particular interest to astronomers as they can be used to learn about stellar evolution. They are also vital in the study of stellar wind, ionized nebulae, and accretion because of the unique interstellar dynamics present within the system. Many symbiotic binaries show brightness changes and are classified as variable stars. The star Z Andromedae is often considered the prototype of the symbiotic binary class of stars. More commonly it is considered as the prototype of only a subset of symbiotic stars with irregular variations up to about 4 magnitudes in amplitude. Even the Z Andromedae variable stars are thought to be an inhomogeneous group. The so-called symbiotic novae are a closely related class of symbiotic binaries, more formally known as type NC novae. They appear similar to classical novae but have extremely slow outbursts that can remain near maximum brightness for years.