Some hundred and fifty light-years away, in the quiet old cluster of the Hyades that sits among the stars of Taurus, a handful of unseen stars may be something stranger: black holes, perhaps two or perhaps three, lingering near the cluster's heart or having recently been flung from it. No one has seen them directly. Their presence is inferred from the slow, delicate choreography of the cluster's stars, read through the precise measurements of the Gaia telescope and tested against the long simulated history of how such a family of stars ages and drifts. If the inference holds, these would be th
Astronomers Suggest Two or Three Black Holes May Lurk in the Hyades, Closest Yet to Earth
Roughly ten times closer than the previous record holder
Mark
Why does a cluster 150 light-years away matter so much when we already knew of black holes at 1,560?
Mimi
Because it's about ten times closer than Gaia BH1. And the Hyades is a well-studied cluster, so it's a good place to test how black holes shape the stars around them.
Mark
How did they find them without seeing them?
Mimi
They simulated the cluster with and without black holes, then compared the results to Gaia's measurements of star positions and velocities. Two or three black holes fit best.
Luke
Let me slow that down. Nobody has detected a black hole here. It's a model match, not an observation.
Mimi
Fair. The team says the simulations match the cluster's mass and size only if black holes are there now or were until recently.
Mark
What does 'until recently' mean?
Mimi
Models with black holes ejected within the last 150 million years also fit. The cluster is about 625 million years old at the quarter mark, and the stars wouldn't yet have erased the evidence.
Luke
So the data can't tell us whether they're still inside the Hyades. That's still unknown.
Mimi
Right, though the simulations suggest ejected ones would still be near the cluster, so the closest-record claim holds either way.
Luke
Holds in the simulations, to be precise. Direct confirmation hasn't happened yet.
O Pulso
- Two or three black holes may be hiding within the Hyades, roughly 150 light-years from Earth, yet none has been seen directly.
- Simulations matched against Gaia's measurements of star positions and motions point toward their presence, prompting a rethink of the record for closest black hole.
- The candidates would sit about ten times nearer than Gaia BH1, unsettling the previous sense of how far away such objects must lie.
- Even if the black holes were ejected long ago, the models suggest they still wander close to the cluster, keeping the question open.
- Until direct observations arrive, the discovery remains a compelling inference that waits for confirmation.
Some hundred and fifty light-years away, in the quiet old cluster of the Hyades that sits among the stars of Taurus, a handful of unseen stars may be something stranger: black holes, perhaps two or perhaps three, lingering near the cluster's heart or having recently been flung from it. No one has seen them directly. Their presence is inferred from the slow, delicate choreography of the cluster's stars, read through the precise measurements of the Gaia telescope and tested against the long simulated history of how such a family of stars ages and drifts. If the inference holds, these would be the nearest black holes ever found to our world, a reminder that the closest mysteries are sometimes the ones we have been passing all along.
In Taurus, the Hyades, an open cluster of several hundred stars about 150 light-years from the sun, may be harboring two or possibly three black holes. If confirmed, they would be the closest black holes to Earth yet identified.
The work was led by Stefano Torniamenti of the University of Padua. His team did not look for the black holes directly. Instead they built a simulation of how the cluster's stars move and evolve, included black holes in the calculations, and compared the results with real position and velocity data from the Gaia space telescope. The models that matched best contained two or three black holes. Torniamenti noted that the cluster's mass and size can be reproduced together only if some black holes sit at its center now, or did until recently.
That qualification matters. Scenarios in which black holes were ejected up to 150 million years ago also fit the data, since a cluster around 625 million years old may not yet have erased the traces of their presence. Even then, the simulations suggest the black holes would remain near the Hyades, drifting through the galaxy as rogue objects.
The Hyades is a useful test case because its stars formed together from the same cloud and share age and composition. Gaia, launched in 2013, makes such inferences possible by tracking billions of stars with great precision, revealing unseen masses through their gravitational tugs. Compared with Gaia BH1 and BH2, the previous record holders, these candidates would be far closer.
Mark Gieles of the University of Barcelona, also on the team, said the findings could clarify how black holes shape star clusters and how they are spread across the galaxy. For now, though, the result rests on simulation. Only further observation can show whether the black holes are really there, or have already left.
In the constellation Taurus sits the Hyades, an open cluster of several hundred stars about 150 light-years from the sun. A team of astronomers now suggests that two, or possibly three, black holes may be hiding in or near it. If they are right, those objects would be the closest black holes to Earth yet identified.
The work was led by Stefano Torniamenti, a postdoctoral researcher at the University of Padua. His team did not spot the black holes directly. They built a simulation of how the Hyades' stars move and change over time, and they included black holes in the calculations. They then compared the output with real measurements of the positions and velocities of the cluster's stars, data that come from the Gaia space telescope.
The models that best matched what Gaia has seen were the ones that contained two or three black holes inside the cluster. Torniamenti said in a statement that the simulations can match the Hyades' mass and size at the same time only if some black holes sit at its center today, or did until recently.
That last phrase matters. Simulations in which black holes were violently thrown out of the cluster no more than 150 million years ago also fit the Gaia data. The team's reasoning is that if the ejection happened when the Hyades was about a quarter of its present age, roughly 625 million years old, the cluster would not yet have evolved enough to erase the evidence that the black holes had been there.
Even in that scenario, the researchers say, the black holes would still be the nearest to Earth. The simulations indicate that any that have left the Hyades remain close to it, wandering the galaxy as rogue objects.
The Hyades is an open cluster, a group of stars believed to have formed together from the same giant cloud of gas and dust. Its members therefore share basic traits such as age and chemical composition, which makes the cluster a useful test case for models like this one.
The previous record holders were Gaia BH1 and Gaia BH2, both identified with Gaia data earlier in 2023. Gaia BH1 lies about 1,560 light-years away and Gaia BH2 about 3,800. By the source's comparison, the Hyades candidates would be roughly ten times closer than the first and more than twenty times closer than the second.
Gaia, launched in 2013, makes this kind of inference possible. It measures the positions and motions of billions of stars against the background sky with great precision, and for the first time it lets astronomers study individual stars in clusters like the Hyades. Small gravitational tugs on those stars can reveal objects that cannot be seen, including stellar-mass black holes.
Mark Gieles of the University of Barcelona, another researcher on the study, said the result helps explain how black holes affect the evolution of star clusters. He added that it also offers insight into how these objects are distributed across the galaxy.
The finding rests on simulation and inference, not direct detection. Confirming whether two or three black holes are really there, or have recently left, will depend on further observation.
Citações Notáveis
Our simulations can only simultaneously match the mass and size of the Hyades if some black holes are present at the center of the cluster today, or until recently.— Stefano Torniamenti, University of Padua
The observation helps us understand how black holes affect the evolution of star clusters and how these objects are distributed across the galaxy.— Mark Gieles, University of Barcelona (paraphrased)
Quer a matéria completa?
Leia o original em Space.com ↗
Science & Space