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Дата изменения: Fri Jan 25 15:33:06 2002
Дата индексирования: Tue Oct 2 09:36:57 2012
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Spectrum

Many light-curve identifications were made retrospectively from photographic plates originally obtained to patrol the sky for asteroids, supernovae and other variable phenomena. As a consequence the light curves were often incomplete so that symbiotic, cataclysmic and semi-regular variables were sometimes identified as RCBs.

RCB stars have a spectrum which resembles that of an F or G supergiant. The Balmer lines of hydrogen are unusually weak or absent, there are many lines of neutral atomic carbon and strong bands of molecular carbon (C${_2}$ and CN). In one of the earliest analyses of stellar surface composition, it was shown that RCrB itself was extremely hydrogen-deficient ([Berman 1935]). These characteristics have enabled the identification of 34 RCB stars in the Galaxy to be confirmed (cf. [Clayton 1996], [Jeffery et al. 1996]).

There is a small group of early-type stars reputed to show RCB-type light curves and also have weak Balmer lines. These hot RCB stars will be discussed later.