One star in this constellation is the prototype for a class of pulsating stars with light curves having alternating deep and shallow minima. Another star in this constellation names a class that descends almost-vertical lines on a Hertzsprung-Russell diagram called Hayashi tracks before joining (15[1])the main sequence; that is the T star of this constellation. (15[1])A nebula in this constellation (15[1])names a unit of X-ray intensity due to formerly being used as a standard candle in X-ray astronomy. That nebula is the remnant of a (*) 1054 supernova recorded by Chinese astronomers. A star cluster in this constellation is surrounded by a prominent blue reflection nebula and is the brightest Messier object. For 10 points, name this constellation containing the Crab Nebula and the Pleiades, a zodiacal constellation named for a bull. ■END■