centaurus
Alpha Centauri is the brightest star in the Centaurus constellation, the "Centaur".
The brightest star in a constellation is known as the alpha star. It is typically designated as the first letter of the Greek alphabet followed by the genitive form of the constellation name. For example, Alpha Centauri is the brightest star in the Centaurus constellation.
It's the brightest star in the constellation Centaurus. Star names are assigned based on the genitive form of the name of the constellation they're in, with the brighter stars (usually) being given low Greek letter names.
As the name implies, Alpha Centauri is the brightest star in the constellation Centaurus, the Centaur.
Rigel is in the constellation Orion, not Centaurus. Please check your spelling and, if appropriate, resubmit.
Alpha Centauri (the brightest star in the constellation Centaurus) is the closest star to earth, and is actually a double star system - when it's small companion star is on "our side" of Alpha C, it is actually closest. The system is about 4.3 light years away. Sirius is the brightest star in the night sky, a white giant, and is about 9 light years away.
Rasalhague is the brightest star in the constellation Ophiuchus
The Rigel star is a star in the Orion constellation. Rigel is the brightest star in the Orion constellation, and it is the seventh brightest star seen in the night's sky.
That would be one of the members of the multiple-star system that appears as the brightest star in the southern constellation "Centaurus". The system was never given any particular name, and is simply referred to as "Alpha Centauri", which just means the "brightest star in Centaurus". It's about 4.4 light years from our solar system, which is something like 25,900,000,000,000 miles.
Spica is the brightest star in the constellation Virgo.
The Centaurus is the third largest star in the Southern Cross. The other two stars in the Southern Cross are named Alpha and Beta Centaurus.
The closest star to the Sun, Proxima Centauri, is part of the southern constellation of Centaurus. Centaurus is one of the largest constellations in the sky and is best seen from southern latitudes.