Astrophysicists have cracked the mystery of the binding force behind a cluster of unruly and rapidly swirling stars located in the famous Sword of Orion. Using sophisticated computer modelling, they found these fast-moving stars, known as the Orion Nebula Cluster, were potentially held together by the gravitational pull of a black hole up to 200 times the mass of the Sun.
Formed one or two million years ago, the Cluster has long been known for its strange properties. Its stars move at a rapid speed, as if the whole cluster was flying apart, reported the Astrophysical Journal.
Compared to the number of light-weight stars that can be seen in the cluster, the number of heavy-weight stars are too few and especially rapidly-moving, according to a Queensland statement. "These properties have been a puzzle to astronomers, given all the knowledge that they have about how stars are formed and distributed," said Holger Baumgardt from the University of Queensland's School of Mathematics and Physics, who co-authored the study,
"In our model, we had to invent a new method of dealing with the gas and the way it is driven out from the cluster by the intensely radiating high-mass (heavy weight) stars," said Ladislav Subr, of Charles University in Prague, who led the study.
Many of the heavy stars were sling-shot out of the cluster, while some were driven into the centre of the cluster and collided with the most massive star there. At some point, this massive star became unstable and imploded into a black hole, with a mass about 200 times larger than the Sun.
"Our scenario neatly accounts for virtually all observed properties of the Orion Nebula Cluster, that is, its low number of high-mass stars, and its rapidly-moving central stars, and suggests that the massive stars near the centre of this cluster are bound by a black hole," Subr said.