While there are many things hiding in the vastness of the cosmos, black holes are something that’s so huge they are fairly noticeable. However, that not the case. A new study published in the journal Nature, claims to have discovered more than 100 stellar-mass black holes hiding in the cluster of stars moving across our galaxy.
While that sounds alarming, none of these black holes are close enough to be a threat. They are so far that astronomers are taking them as an opportunity to study more about these newly found mysterious objects.
80,000 light-years from Earth
The cluster of interest is called Palomar 5 that is around 80,000 light-years away from Earth, with the stars themselves are 30,000 light-years away from one another within the cluster. But it’s the black holes that have been attracting astronomers.
“The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20% of the total cluster mass is made up of black holes,” said Mark Gieles, lead author of the study.
“They each have a mass of about 20 times the mass of the Sun and they formed in supernova explosions at the end of the lives of massive stars when the cluster was still very young.”
First evidence of tidal streams
The discovery has allowed them to classify Palomar 5 as a tidal cluster and not a globular cluster. The main difference between the two is the spread of stars – globular clusters have stars that were formed around the same time, while tidal clusters pack stars of different ages that are distributed loosely in a stream.
This is the first evidence of the origin of tidal streams. Now, with more analysis of the cluster, the team was able to use N-body simulations to recreate the orbits and evolutions of the stars that form this cluster. The findings show that the tidal stream of the cluster was formed due to a significant number of black holes taking stars out of the cluster. This discovery will allow scientists to study how tidal streams are formed.
