Shell star variables. Pleione and Gamma Cassiopeiae itself are both variable stars that have intermittent shell episodes where strong shell features appear in the spectrum and the brightness increases or decreases significantly. At other times the shell is not detectable in the spectrum, and even the emission lines may disappear. 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,
Luca (given name) Luca (given name) Luca (also spelt Louca, Luka, Louka, Lucca) is a given name used predominantly for males, mainly in Latin America, Italy, Spain, Portugal, Romania, Russia, Serbia, Slovenia, Croatia, Bulgaria, Greece, Georgia and Armenia. It is derived from the Latin name Lucas, which itself is derived from the Latin word "lux" (light). It may also come from the Latin word "lucus" meaning "sacred wood" (a cognate of lucere). The name is common among Christians as a result of Luke the Evangelist. Similarly, the name Luka is also commonly found as a male given name in Eastern Europe and particularly