Hadar (also known as β Centauri) is not a main sequence star. It is a blue giant star, which is a type of star that has evolved beyond the main sequence stage.

Here's why:

* Main sequence stars are stars that are fusing hydrogen into helium in their cores. This is the longest and most stable stage of a star's life.

* Blue giants are much larger, hotter, and more luminous than main sequence stars. They have already exhausted their hydrogen fuel and are now fusing heavier elements like helium in their cores.

Hadar is a massive star with a mass about 10 times that of our Sun. It has already left the main sequence and is now in the later stages of its life. It will eventually become a red supergiant and eventually explode as a supernova.