Hereford Arizona Observatory found fluctuations in what type of main-sequence star in Cygnus?
KIC 8462852 KIC 8462852 (also Tabby's Star or Boyajian's Star) is an F-type main-sequence star located in the constellation Cygnus approximately 1280 ly from Earth. Unusual light fluctuations of the star, including up to a 22% dimming in brightness, were discovered by citizen scientists as part of the Planet Hunters project, and, in September 2015, astronomers and citizen scientists associated with the project posted a preprint of an article describing the data and possible interpretations. The discovery was made from data collected by the "Kepler" space telescope, which observes changes in the brightness of distant stars to detect exoplanets.
V380 Orionis V380 Ori is a young multiple star system located near the Orion Nebula in the constellation Orion, thought to be somewhere between 1 and 3 million years old. One of the component stars appears to have launched a polar jet that helped to clear the keyhole-shaped hole in the surrounding nebula known as NGC 1999. The system is surrounded by a bow shock—the total structure over 17 light-years (5.3 parsecs) across. V380 Orionis is a quadruple star system. The two main stars (until now known collectively as V380 Orionis Aa) are a spectroscopic binary system, the stars orbiting each other over a period of 106 days. The primary is a hot white Herbig Ae/Be star of spectral type B9 that has a surface temperature of 10,500 ± 500 K, and is around 2.87 times as massive and 100 times as luminous as the Sun, and is triple its diameter. The secondary is a T Tauri star that has a surface temperature of 5,500 ± 500 K, and is around 1.6 times as massive and 0.31 times as luminous as the Sun, and is twice its diameter. The two stars are surrounded by a circumstellar disk, lying almost edge-on to observers on earth.