英和和英

出典:『Wikipedia』 (2010/03/16 05:34 UTC 版)

英語による解説

引用

In astronomy, a common envelope (CE) refers to a short-lived (months to years) phase in the evolution of a binary star in which the largest of the two stars (the donor star) has initiated unstable mass transfer to its companion star. Mass transfer is unstable when the radius of the donor star expands more rapidly or shrinks less rapidly than does the binary orbit. Hence, the donor will start mass transfer when it overfills its Roche lobe and as a consequence the orbit may shrink while the star expands, causing it to overflow the Roche lobe even more, which accerelates the mass transfer, causing the orbit to shrink faster and the donor to expand faster, etcetera. This leads to the run-away process of dynamically unstable mass transfer. The result will be the fast expansion of the donor's stellar envelope, which will then engulf the companion star. Hence the name common envelope.