The process of how black holes eat and digest stars involves an interesting phenomenon that can best be described as “burping”, according to the astronomers.
In the study – published November 26 in the journal Science – the astronomers observed a black hole swallowing a star. From the observations they found that when a supermassive black hole ‘eats’ and ‘digests’ a star, it releases a small amount of star material back into the universe in the form of a thermal flame.
Over the course of several months, the scientists looked at one particular star. They used radio telescopes to track said star and make their observations.
The astronomers saw that when the star got sucked in by the black hole, plasma escaped from the supermassive black hole’s event horizon (boundary in spacetime; a point at which the gravitational pull is so strong that nothing can escape it). They named this event ASASSN-14li.
Sjoert van Velzen, lead author of the study and a Postdoctoral Hubble Fellow at The Johns Hopkins University (JHU) in Baltimore, Maryland, said that these types of events are exceptionally rare. This is the first time that astronomers were able to observe the destruction of a star, followed by the launch of a jet, also referred to as conical outflow. They watched these events unfold over a period of several months.
A black hole is defined as a region of spacetime which has a density so high that nothing – from different particles to electromagnetic radiation – can escape it. It is a compact mass that forms from the remains of very massive dead stars.
Because supermassive black holes are invisible to humans (due to their structure), scientists usually find a black holes by observing how they interact with neighbouring stars and the interstellar medium (ISM), which includes gas, cosmic rays, and dust.
The team first had to confirm that the release of plasma came from the supermassive black hole swallowing a star and not something else. The astronomers’ observations turned out to be correct, and so they confirmed a previous hypothesis which stated that a short-lived thermal flame may occur due to the tidal disruption of a star by a black hole.
Another team of scientists at Harvard University in Cambridge, Massachusetts has been making similar observations using radio telescopes.
In November, both of the teams – from John Hopkins University and Harvard University – met up at a workshop in Jerusalem and presented their findings. Sjoert van Velzen said that the meeting was a very productive exchange of ideas on the supermassive black hole topic.
Image Source: api.hub.jhu