Quasi-star

A quasi-star, also known as black hole star, is a hypothetical type of star believed to have existed in the beginning of the universe when most of the existing material was hydrogen and helium. Instead of a normal nuclear fusion core, the core of a quasi-star would be a black hole.

 Formation and properties 
Quasi-stars are stars that were so massive that while they were still alive, their cores became a black hole. But, the quasi-star didn't go supernova like in normal stars today. The star was so big that the supernova happening inside the star didn't destroy it.

These quasi-stars might have been made in dark matter halos. The gravity of these dark matter halos brought in a lot of gas, which created very big stars.

Normally in stars today, nuclear fusion stops the star's gravity from crushing it. But in quasi-stars, the black hole inside causes matter from the star to move around it. This releases a lot of energy and stops the star's gravity from crushing the star. 

Quasi-stars lived for about 7 million years. The black hole at the center of the star could grow up to 1,000 to 10,000 solar masses. If quasi-stars existed the black holes they created could have become the supermassive black holes we see at the center of most galaxies, including our own Milky Way. Quasi-stars were very very very big, as big as our solar system. They were also as bright and heavy as a small galaxy.

If quasi-stars existed they could explain one of the biggest mysteries in cosmology. Black holes could only get so big from merging or eating a lot of things. Eating a lot is not very efficient since it could take millions of years to devour a star that is, say, 10 solar masses. Merging, or when two black holes collide, is a little more efficient, but it's not enough to explain how there were supermassive black holes millions of solar masses just a few hundred million years after the Big Bang. Because quasi-stars could make black holes that were thousands of solar masses, these massive ones could be the ones that merged and became the supermassive black hole.

 Related pages 
 Quark-star
 Black hole
 Accretion disk
 Neutron star
 Quasar

 References 

Category:Black holes