GK Per: Nova and Planetary Nebula
The star system GK Per is known to be associated with only two of the three nebulas pictured . At 1500 light years distant, Nova Persei 1901 ( GK Persei ) was the second closest nova yet recorded. At the very center is a white dwarf star , the surviving core of a former Sun-like star. It is surrounded by the circular Firework nebula , gas that was ejected by a thermonuclear explosion on the white dwarf's surface -- a nova -- as recorded in 1901 . The red glowing gas surrounding the Firework nebula is the atmosphere that used to surround the central star. This gas was expelled before the nova and appears as a diffuse planetary nebula . The faint gray gas running across is interstellar cirrus that seems to be just passing through coincidently. In 1901, GK Per's nova became brighter than Betelgeuse . Similarly, star system T CrB is expected to erupt in a nova later this year, but we don't know exactly when nor how bright it will become.