The simple answer is that it does not: it does not even feature in the top ten!
That's NOT the brightest star known.
Gamma Orionis (Bellatrix) is the third brightest star in the constellation Orion.It has an apparent magnitude of 1.64 and an absolute magnitude of -2.72.This makes it the 27th brightest star in the nighttime sky.
The simple answer is that it does not. It is important to note that stars radiate across a whole range of electromagnetic frequencies, not just in the visible part of the spectrum. Astronomers use bolometric absolute magnitude to adjust for the fact that a star may be radiating much of their energy outside of the visible range. Using the bolometric absolute magnitude, the brightest star, with magnitude -12.5 is RMC136a1 in the Large Magellanic Cloud, at a distance of 163000 light years.Among stars visible to the naked eye, Bellatrix does not even make it to the top ten in terms of its bolometric absolute magnitude. That distinction goes to P Cygni with an absolute magnitude of -9.7. It is 5900 light years away. In comparison, Bellatrix has a magnitude of only -2.64
Alpha Persei (Mirfak or Algenib) is the brightest star in the constellation of Perseus.It has an apparent magnitude of 1.79 and an absolute magnitude of -4.50
The absolute magnitude
No. The sun has an absolute magnitude of 4.83. By comparison, Betelgeuse has an absolute magnitude of -5.85. Lower numbers indicate a brighter star. In this case Betelgeuse is actually several thousand times brighter than the sun. The sun is the brightest star as measure by apparent magnitude, which is how bright a star looks from a given location and depends on both absolute magnitude and distance.
Acrux is the brightest star in the constellation Crux.It has an apparent magnitude of +0.77It has an absolute magnitude of -4.14
Rigel is the brightest star in the constellation Orion.It has an apparent magnitude of 0.18 and an absolute magnitude of -6.7
The "Amazon" star, Bellatrix, has a surface temperature around 40,000*F and has a mass ten times greater than that of our sun!
Rigel is the brightest star in Orion and the sixth brightest star in the sky, with an apparent magnitude of 0.18.
Beta Centauri (Hadar or Agena) is the second brightest star in the constellation Centaurus.It has an apparent magnitude of 0.6 -> 0.8 (It's a variable star) or an absolute magnitude of -4.57
That is Sirius. Its "apparent magnitude" is minus1.5 approximately. Sirius is the brightest star in the sky for us on Earth, but it's not the most luminous star in "absolute magnitude". The main reason that it is so bright is just that it is very close to us.
The second brightest star is Canopus with an apparent magnitude of -0.72The brightest is Sirius with an apparent magnitude of -1.47