Supermassive black holes are found at the centre of galaxies.
Credit: NASA/JPL-Caltech
SYDNEY: Stars more than one million times as massive as the Sun may be more stable than astronomers thought, and have created seeds that grew into the largest supermassive black holes.
Supermassive black holes are found at the centre of most galaxies, including our own Milky Way. Theories about their formation range from collapsing clouds of gas to collisions between smaller black holes.
Astrophysicists have also suggested that supermassive black holes could have formed from the catastrophic collapse of incredibly large stars that were one million to one billion times the mass of the Sun.
Extreme instability
These hypothetical stars would be extremely unstable. The process of forming the black holes must have happened rapidly, say experts, as these stars could only exist for around four million years, accumulating matter at a rate exceeding about one solar mass per year. This is in contrast to the our roughly 4.5-billion-year-old Sun.
To find out if huge stars could create supermassive black holes, astrophysicist Mitchell Begelman from the University of Colorado in Boulder, USA, modelled the structure and evolution of stars more than a million times the mass of the Sun.
He found that, if they were stabilised by rotation or magnetic forces, the stars could have created seed black holes a few per cent of the star's mass; about 10,000 to 100,000 times the mass of the Sun.
"Bloated, turbulent envelope of gas"
Once these seeds form, the stars inflate into what Begelman calls a quasistar — a bloated, turbulent envelope of gas powered by black hole accretion at the centre of the star. His research will appear in the Monthly Notices of the Royal Astronomical Society.
"Because of the likely importance of rotation in the collapsing core, only a small fraction of the supermassive star collapses to a black hole initially. The energy liberated during the formation of the black hole inflates the remainder of the star into a bloated object that resembles a red giant, which we have previously termed a 'quasistar'," Begelman says.
At a certain point, radiation begins to leak out of the star and blows the remains of it apart. The black hole 'seed' then rapidly grows into a supermassive black hole.
Black-Hole Is Stem-Star
Every generation of stars (galaxy), radiate from Black hole- the Stem-Star, out of which, and into which, generations of stars recycle.
-Aiya-Oba (Philosopher)
Black holes
So are these things currently just sucking in more and more cosmic things over a few seconds or does it take like a year or something to reach the center?