Astrophysics (index)about

Be star

(early star with Balmer emission lines)

A Be star is an early star, generally a B-type star, with emission lines such as hydrogen Balmer lines. Such an A-type star might be lumped in as a Be star or alternately, might be termed an Ae star. The same for an O-type star.

Current theory is that Be stars are rotating rapidly, and heating a circumstellar disk of gas ejected by the rotation. Many show overlaid H-alpha emission and absorption lines, each with considerable line broadening, the former indicating the rotation of the disk and the latter, the rotation of the star.

A Be star and a B(e) star are different types, the latter being a B-type star with forbidden emission lines.


(star type,Balmer series)
http://en.wikipedia.org/wiki/Be_star
http://www.astrosurf.com/buil/us/bestar.htm

Referenced by:
decretion disk

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