GK Persei nova remnant, composite image. Novae are outbursts of energy caused by material falling onto a white dwarf from its companion star. Also known as Nova Persei 1901, this nova was first observed in 1901. It has periodically recurred since, with regular outbursts since 1980. It is thought to have changed from a classical nova to a cataclysmic variable star. The gas and dust cloud surrounding GK Persei is known as the Firework Nebula. GK Persei is around 1560 light years from Earth, in the constellation of Perseus. Here, the image combines X-ray data (blue) from the Chandra X-ray Observatory (CXO), optical data (yellow) from the Hubble Space Telescope (HST) and radio data (pink) from the Very Large Array (VLA). Image published in 2015.