Collisions between the remains of monstrous stars, with masses reaching 200 - 300 times that of our Sun, will not
occur until billions of years from now, according to astrophysicists from the Astronomical Observatory of the
Faculty of Physics at University of Warsaw.
For a long time, astronomers have believed that the biggest stars in the Universe do not exceed 150 solar masses.
However, three years ago star clusters in the Magellanic Clouds were discovered to house "impossible" stars --
tremendous monsters with masses between 200 and 300 times that of our own Sun.
Click on image to enlarge
Stellar Titans of Pismis 24. Credit: ESO/IDA/Danish 1.5 m/ R. Gendler, U.G. Jørgensen, J. Skottfelt, K. Harpsøe
The discovery aroused great interest among astrophysicists, in particular those involved in the century-long search
for gravitational waves. If such stellar monsters formed tight binary systems, collisions between their remnants could occur.
The gravitational waves resulting from such an event would be powerful enough that even our current detectors
could sense them -- and at distances much larger than for typical stellar black holes.
"But we cannot count on detecting any such spectacular collision," says Dr. Krzysztof Belczy?ski of the Astronomical
Observatory of the Faculty of Physics at the University of Warsaw.
Stars with large masses may end their lives in two ways: their material can be blown into space or they
can collapse under their own gravity into a black hole.
A few months ago, astrophysicists led by Dr Norhasliza Yusof at the University of Kuala Lumpur demonstrated
that some supermassive stars can form black holes.
This means that the universe might indeed play host to binary systems of supermassive stars which later evolved
or transformed into systems of two black holes with masses much larger than these typically observed for black holes.
Objects orbiting in tight binary systems composed of neutron stars or ordinary black holes lose their energy
over time, leading to closer and closer orbits and finally a collision.
Such a collision may have the astronomically observable effect of a powerful gamma-ray burst, and the explosion
should also be accompanied by the emission of gravitational waves.
However, up to now we have failed to observe these waves.
Current detectors can only "see" the collision of typical black holes in the local Universe.