SYDNEY, Aug 21 (NNN-AAP) – Australian scientists have made a breakthrough in understanding how stars are torn apart and consumed by black holes, through innovative simulations.
In a new study, a team from Monash University captured the fate of stars that drift too close to supermassive black holes, by simulating how the process, known as tidal disruption, evolves over the course of a year, said a media release, yesterday.
Daniel Price, leader of the research team from Monsh’s School of Physics and Astronomy, said that, it was the first self-consistent simulation of a star being destroyed by a supermassive black hole, and the evolution of the resulting debris over a year.
“Our simulations provide a new perspective on the final moments of stars in the vicinity of supermassive black holes,” Price said.
A tidal disruption event (TDE) is a phenomenon that occurs when a star passes close to a supermassive black hole, at the centre of a galaxy and is pulled apart by its tidal force. The star undergoes spaghettification, meaning it is stretched vertically and compressed horizontally as it falls towards the black hole.
The theory of TDEs was developed in the 1970s and 1980s, but many aspects of the process remain unknown.
The new simulation explains how debris from TDEs forms a bubble around the black hole, reprocessing the energy and producing observed light curves with lower temperatures and fainter luminosity than expected, from models of black holes efficiently eating material.
The X-rays the black hole emits are absorbed by the bubble – called an Eddington envelope – and re-emitted as optical light, explaining why TDEs are observed at optical rather than X-ray wavelengths, and why observed temperatures are consistent with the photosphere of a star rather than the expected hot accretion disk of material in motion around a black hole.
“A good analogy is the human body: when we eat lunch, our body temperature does not change much, this is because we reprocess the energy from lunch into infrared wavelengths. A TDE is similar, we mostly do not see the black hole stomach eating gas, because it is smothered by material that reemits at optical wavelengths. Our simulations show how this smothering occurs,” Price said.
The project also included researchers from Columbia University in the United States and the University of Milan in Italy.– NNN-AAP
