Astronomers could have discovered that the closest black holes to Earth might be lurking within the Hyades Cluster, which sits only around 150 light-years from the sun.
In truth, these black holes could have been ejected from the dense cluster of stars thousands and thousands of years ago to wander the galaxy alone. Even so, they’d still be around ten times as close because the black hole previously considered the closest to Earth.
Visible within the constellation of Taurus, the Hyades is an open cluster of lots of of stars. Open clusters like this one are collections of stars believed to have formed at the identical time from the identical massive cloud of gas and dirt. Due to that, stars inside this sort of cluster are known to share foundational characteristics like chemical compositions and ages.
As a way to make the detection of what might be the closest black holes to our planet, a team led by Stefano Torniamenti, a postdoctoral researcher on the University of Padua, created a simulation of the movements and evolutions of stars within the Hyades. The simulation was also generated with black holes present within the equation. The scientists then compared results from this simulation with actual observations previously product of the velocities and positions of the open cluster’s stellar population. The latter dataset owes itself to the Gaia space telescope.
“Our simulations can only concurrently match the mass and size of the Hyades if some black holes are present at the middle of the cluster today, or until recently,” Torniamenti said in a press release.
Related: Black holes keep ‘burping up’ stars they destroyed years earlier, and astronomers don’t know why
Torniamenti and colleagues found the models which best lined up with observations of the Hyades were those who included two or three black holes contained in the star cluster. Beyond this, simulations that involved black holes within the star cluster which theoretically got ejected not more than 150 million years ago also matched Gaia data.
It is because, the team says, if those black holes had been violently tossed from the Hyades when the cluster was around 1 / 4 of its current age — roughly 625 million years old — the gathering of stars wouldn’t have evolved enough to remove evidence of their prior existence.
Even when the black holes have been ejected from the Hyades by now, the researchers explain, they’d still remain the closest black holes to Earth despite their rogue status. That’s based on the simulations, which indicate that if the black holes aren’t currently within the Hyades, they’re still near it.
Prior holders of the closest-black-hole-to-Earth record were Gaia BH1 and Gaia BH2, which, as their names imply, were uncovered with Gaia data just this 12 months.
Gaia BH1 is positioned 1,560 light-years away from Earth, while Gaia BH2 lies around 3,800 light-years away. Despite the fact that this implies each black holes are positioned in Earth’s backyard (in cosmic terms, a minimum of),they’re still over 10 and 20 times as distant because the Hyades cluster and its potential black hole duo or trio.
Each this latest research and the prior discovery of Gaia BH1 and BH2 exemplify how Gaia, launched in 2013, has been reshaping astronomy. The space telescope made it possible for astronomers to check the positions and velocities of individual stars in clusters just like the Hyades for the primary time.
Gaia is able to such breakthroughs because it will probably accurately measure the positions and motions of billions of stars against a background sky. Tracking stellar movements with such high precision helps to disclose gravitational influences tugging on these stars, even when that influence comes from hidden objects like small stellar mass black holes.
“This commentary helps us understand how the presence of black holes affects the evolution of star clusters,” researcher creator and University of Barcelona researcher Mark Gieles said. “These results also give us insight into how these mysterious objects are distributed across the galaxy.”
The team’s research was published in June within the journal Monthly Notices of the Royal Astronomical Society.