Astronomy Picture of the Day . ... Credit Copyright: STSci Digitized Sky Survey, Anglo-Australian Observatory Explanation: The closest star system to the Sun is the Alpha Centauri system . Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star . The bright stars Alpha Centauri A and B form a close binary as they are separated by only 23 times the Earth - Sun distance - slightly greater than the distance between Uranus and the Sun . ...