Alpha+Centauri+4B

The closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest is called Proxima Centauri and is actually the closest star. The bright stars Alpha Centauri A and B form a close binary as they are separated by only 23 times the Earth and Sun distance and is slightly greater than the distance between Uranus and the Sun.The Alpha Centauri system is not visible in much of the northern hemisphere. Alpha Centauri A, also known as Rigil Kentaurus, is the brightest star in the constellation of Centaurus and is the fourth brightest star in the night sky. Sirius is the brightest even thought it is more than twice as far away. By an crazy coincidence, Alpha Centauri A is the same type of star as our Sun, causing many to speculate that it might contain planets that harbor life. Not only because it is the closest stellar system to the sun but also because it is one of the relatively few places in the Milky Way Galaxy that may offer alien life conditions. If humans look for alien life elsewhere, then Alpha Centauri is a perfect place. only seen from latitudes south of about 25° the star we call Alpha Centauri lies 4.35 light-years from the Sun. It is actually a triple star system. They orbit each other in 80 years with a mean separation of 23 astronomical units. The third member of the system Alpha Centauri C lies 13,000 from A and B, or 400 times the distance between the Sun and Neptune. This is so far that it is not known whether Alpha Centauri C is really bound to A and B, or if it will have left the system in some million years. Alpha Centauri C lies measurably closer to us than the other two: It is only 4.22 light-years away, and it is the nearest single star to the Sun. This is a proximity, Alpha Centauri C is also called Proxima (Centauri).

Alpha Centauri A, also known as Rigil Kentaurus, is the brightest star in the constellation of Centaurus. Next to the two bright stars is the Coalsack, and to the right of that is Crux (the Southern Cross).