Betelgeuse, also known by its Bayer designation Alpha Orionis (α Orionis, α Ori), is the ninth brightest star in the night sky and second brightest star in the constellation of Orion, outshining its neighbour Rigel (Beta Orionis) only rarely.
A scientist in Australia says that Betelgeuse, which is something like 640 light years away, appears to be losing mass at a fairly rapid rate. If that happens the star could go supernova, which would produce such a blindingly bright, uh, image, that it would be as visible in our sky as a second sun. With Betelgeuse losing mass, an explosion will create a new sun. Maybe that will happen in 2012.
Betelgeuse is more than 20 times the mass and more than 1,100 times the diameter of our sun, giving Betelgeuse an estimated girth of about one billion miles across. It's so large that if you put it in the place of our sun in our solar system, the planets Mercury, Venus, Earth, Mars and even Jupiter would be living inside Betelgeuse.
Betelgeuse's diameter and reddish hue are due to the fact that it's already near the end of its very short life. Most astronomers estimate that Betelgeuse isn't much more than a few million years old and it's already expended its hydrogen and helium fuel to the point where it's puffed out in the red giant phase of its brief life.
The future fate of Betelgeuse depends on its mass—a critical factor which is not well understood. Since most investigators concede a mass greater than 10Mo, the most likely scenario is that the supergiant will continue to burn and fuse elements until its core is iron, at which point Betelgeuse will explode as a type II supernova. During this event the core will collapse, leaving behind a neutron star remnant some 20 km in diameter.
Betelgeuse is already old for its size class and is expected to explode relatively soon compared to its age. At its current distance from Earth, such a supernova explosion would be the brightest recorded, outshining the Moon in the night sky and becoming easily visible in broad daylight.
