A new class of space objects looks like a gas cloud but behaves like a star.
Astronomers have discovered a new class of space objects near the Milky Way’s supermassive black hole, Sagittarius A *. According to an article published by the team in Nature, the nature of the observed phenomenon is still unknown – and its somewhat bizarre behavior.
That’s because these objects look like clouds of gas, but behave like stars. They look compact most of the time, but their orbits lengthen when they approach the black hole and can last from 100 to 1000 years.
A similar object was observed in 2005
The first time that experts noticed an object of this type was in 2005, which was later named G1. In 2012, the discovery was repeated, and astronomers called the observed phenomenon G2. “At the moment of the closest approach [of the black hole], the G2 had a really strange signature,” said Andrea Ghez, one of the researchers, in a statement.
“We’ve seen this before, but it didn’t seem very peculiar until it got close to the black hole and stretched, with much of its gas being destroyed,” explained Ghez. “It went from being a very innocuous object while it was away from the black hole, to [becoming] an extremely stretched and distorted [object] in a closer approach, losing its outer layer – and now it’s getting more compact again.”
It could produce an impressive “fireworks show”
“One of the things that got everyone excited about the G objects is that things that are pulled out of them by the forces of gravity as they pass through the central black hole must inevitably be sucked into it,” said co-author Mark Morris. “When that happens, it could produce an impressive ‘fireworks show’, as the material consumed by the black hole will heat up and emit abundant radiation before it disappears on the event horizon.”
How these objects are formed
Years after the discovery of G2, objects G3, G4, G5, and G6 were also found. For Ghez and his team, responsible for the most recent study on these objects, the “Gs” are the result of the union of systems of binary stars that, because of the black hole, ended up merging.
“Star fusions may be happening in the universe more often than we thought and are probably quite common,” said Ghez. “Black holes may be causing binary stars to merge. Many of the stars that we have been watching without being able to understand could be the end product of these mergers. “
There’s much we don’t know yet
According to the expert, we are still learning how galaxies and black holes evolve. The way these binary systems interact with other stars and black holes is very different from how single stars behave. Ghez hopes that his studies will help astronomers better understand these differences.