This is GK Persei, an object that became a sensation in the astronomical world in 1901 when it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite GK Persei as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star.
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Astronaut Rick Mastracchio During the 5-hour, 28-minute spacewalk on 15 Aug. 2007, STS-118 mission specialist, participates in the mission’s third planned session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. Spacewalks – Blue Sky: credit: NASA