Proxima Centauri

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Proxima Centauri is a red dwarf star approximately 4.2 light-years (3.97 × 1013 km) distant in the constellation of Centaurus. It was discovered in 1915 by Robert Innes, the Director of the Union Observatory in South Africa. The star is the nearest star to the Sun. Its distance to the second and third nearest stars, which form the binary star Alpha Centauri, is only 0.21 ly (15,000 ± 700 astronomical units [AU]). Proxima Centauri may be part of a triple star system with Alpha Centauri A and B, but this is not certain. Because of the proximity of this star, its angular diameter can be measured directly, yielding a diameter one-seventh that of the Sun. Proxima Centauri's mass is about an eighth of the Sun's, and its average density is about 40 times that of the Sun. Although it has a very low average luminosity, Proxima Centauri is a flare star that undergoes random dramatic increases in brightness because of magnetic activity.