Shell star Shell star A shell star is a star having a spectrum that shows extremely broad absorption lines, plus some very narrow absorption lines. They typically also show some emission lines, usually from the Balmer series but occasionally of other lines. The broad absorption lines are due to rapid rotation of the photosphere, the emission lines from an equatorial disk, and the narrow absorption lines are produced when the disc is seen nearly edge-on. Shell stars have spectral types O7.5 to F5, with rotation velocities of 200–300 km/s, not far from the point when the rotational acceleration would disrupt the star.
Douglas (given name) Douglas (given name) Douglas is a Scottish masculine given name which originated from the surname "Douglas". Although today the name is almost exclusively given to boys, it was used as girls name in the seventeenth and eighteenth centuries, in the north of England. The Scottish surname "Douglas" was borne by one of the most powerful families of the Kingdom of Scotland (the Earls of Douglas, Angus, Morton, Dukes of Hamilton and others). It has sometimes been stated that the given name is connected with the given name "Dougal", although it is more likely derived from the surname already mentioned. Linguistically,