Next: Post main sequence stars Up: Principal Evolutionary States of Previous: Principal Evolutionary States of
|
Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://xray.sai.msu.ru/~mystery/articles/review/node6.html
Дата изменения: Tue Feb 25 19:04:52 1997 Дата индексирования: Tue Oct 2 14:11:25 2012 Кодировка: Поисковые слова: http www.starlab.ru showpost.php p 416106 |
Next: Post
main sequence stars Up: Principal
Evolutionary States of Previous: Principal
Evolutionary States of
The star belongs to the zero-age main sequence (ZAMS) and is much smaller
in size than the critical RL. The duration of the first stage is set equal
to the hydrogen burning time, 
, which is a known function of the stellar mass only (Iben and Tutukov,
1987[75]):
The radius of the ZAMS star is
and its luminosity is
The initial mass of the primary and mode of the first mass exchange (which is determined by the initial orbital period and masses of the components; see Webbink, 1979[210]) determine the mass and type of core that will be formed during stage I. For example, for single stars and primaries in type C binaries that fill their Roche lobes having degenerate cores, we use the expressions
where 
is the maximum mass the star attained during its previous evolution and
is the Chandrasekhar limit for WD mass.
A MS-star that accretes matter during the first mass transfer is considered to be a rapidly rotating Be-star that is distinguished by its different stellar wind rate (see below).