The fraction of galaxies described by this adjective in galaxy clusters increases alongside another variable in the Butcher-Oemler Effect. This adjective describes the star Sanduleak -69 202 in a 1987 Nature paper that described that star unusually being a progenitor for a supernova. This adjective names a “loop” that intermediate-mass stars may undergo when they begin burning helium. This adjective describes anomalously young stars in globular clusters like M53, which are called (*) “stragglers” described by this adjective. Visible light is subtracted from light named for this adjective in a common index used on the x-axis of observational H-R diagrams. Along with white, this color describes the color of type-O stars and the star Rigel, which all have low values for color index. Light’s wavelength [emphasize] decreases, and thus energy increases, in this color’s namesake “shift.” For 10 points, what color titles a Voyager 1 photo of Earth as a “pale dot?” ■END■
ANSWER: blue [accept Pale Blue Dot; accept blueshift; accept whitish-blue or bluish-white; accept blue light; accept blue stragglers or blue straggler stars; accept blue supergiant; accept blue loop; accept blue galaxy fraction; accept “Explosion of a blue supergiant: a model for supernova SN1987A”; prompt on B; prompt on B minus V; prompt on supergiant by asking “what other adjective describes that star?”]
<EK, Other Science: Astronomy>
= Average correct buzz position