In 2011, scientists discovered an unusual foggy object whose trajectory showed very clearly that it was flying to meet a supermassive black hole at the center of our galaxy. Interestingly, how rare in astronomy, the meeting was not to take place in a few million years, but three years later. So the scientists got ready and began their observations. But only now have they figured out what the object really was.
Updated version of the previous article.
G2, because that was the designation of the gas cloud, actually approached the supermassive black hole Sgr A * in 2014. At the moment of maximum approximation, under the influence of the black hole's powerful gravity, the object stretched, and then, as it began to move away, it reunited into a slightly more compact cloud.
How did he manage to survive?
Scientists began to wonder what this unusual object is also. Initially, it was even assumed that it would not survive this encounter, and would simply be torn to shreds by gravity first and then absorbed by the black hole. However, this did not happen.
G2 is not only about dust and gas
Analyzing the data from this close encounter, the scientists saw that for a gas cloud, G2 was extremely hot. Yes, you know, meeting a black hole could theoretically heat it up, but the problem is, it was about as hot before the meeting as it was during it. Its temperature, therefore, did not result from the distance to the black hole, but rather was its own peculiarity.
At this point, astronomers began to suspect that there might actually be a star inside the cloud, which was the result of the collision of two other stars. This collision would explain the massive dust cloud near the star.
However, a flight through the perinigricone orbit (the point of orbit closest to the black hole) showed that individual fragments of the stretched cloud still maintained their temperature, so there was hardly a single star in it. Moreover, six other clouds of this type were found in the immediate vicinity of the black hole. It is rather unlikely that there would be six objects formed in the collision of two stars in such a small space.
Three stars and lots of dust
A detailed analysis of the observational data from the last fourteen years has brought exactly the solution to this problem. Scientists argue that the G2 cloud actually hides three extremely young stars estimated to be around one million years old. For comparison, our Sun, which has only lived half of its life so far, is already 4.6 billion years old.
This object was most likely formed as a result of the rupture of a young star cluster. Other objects of the same type are most likely also the remains of the same cluster.
Armed with this knowledge, astronomers now intend to focus on where these stars formed. The immediate vicinity of a supermassive black hole is definitely not the best place for star formation, so the entire star cluster arose elsewhere, further away from the black hole, and only in the course of a (brief) evolution did it come dangerously close to it.