- Stellar wind bubble
Stellar wind bubble is the astronomical term usually used to describe a cavity light years across filled with hot gas blown into the
interstellar medium by the high-velocity (several thousand km/s)stellar wind from a single massivestar of type O or B. Weakerstellar wind s still blow bubble structures though, and these are also called astrospheres. Theheliosphere blown by thesolar wind , within which all the majorplanet s of theSolar System are embedded, is in fact a small example of a stellar wind bubble.Stellar wind bubbles have a two-shock structure [cite journal| url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1975ApJ...200L.107C| last= Castor| first=J.| coauthors=McCray, R., & Weaver, R.| title=Interstellar Bubbles| year=1975| journal=Astrophys. J. (Letters)| volume=200| pages=L107–L110| doi=10.1086/181908] . The freely-expanding
stellar wind hits an inner termination shock, where its kinetic energy is thermalized, producing 106 K,X-ray emitting plasma. The hot, high-pressure, shocked wind expands, driving a shock into the surrounding interstellar gas. If the surrounding gas is dense enough (number densities or so), the swept up gas radiatively cools far faster than the hot interior, forming a thin, relatively dense shell around the hot, shocked wind.References
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