Images from a European space telescope have revealed billions of so-called orphan stars across a single galaxy cluster.
The Perseus cluster is more than 240m light years from Earth and is a massive accumulation of galaxies.
But analysis of the first images captured by the Euclid space telescope shows not all the stars within the cluster have a home.
Euclid is a European Space Agency mission that will create a 3D map of the universe, charting its evolution and the role of dark energy and dark matter in the process.
Among its first pictures, the image of the Perseus cluster shows a dazzling carpet of stars against the dark background of the universe.
The aura of radiant blue light is generated by orphan stars drifting alone through space between the cluster’s galaxies.
Astronomers suggest these lone stars were ripped from the edges of large galaxies or spun out from disruptions to smaller ‘dwarf’ clusters.
After being pulled out of their origin space, galaxies appear to bob around a fixed point between a cluster’s two largest galaxies, rather than being pulled towards the biggest.
To explain how these disturbances could occur, the group behind the analysis think a merger between the Perseus cluster and another band of galaxies could have caused a massive gravitational shake-up.
“We were surprised by our ability to see so far into the outer regions of the cluster and discern the subtle colours of this light,” says University of Nottingham astronomer Nina Hatch.
“This light can help us map dark matter if we understand where the intracluster stars came from. By studying their colours, luminosity, and configurations, we found they originated from small galaxies.”
The image was first released in November 2023, showing the thousands of Perseus galaxies surrounded by hundreds of thousands more in space. Most had never been seen before.
Rather than being a single ‘point-and-click’ of Euclid’s visible light and near-infrared cameras, the image was taken over 5 hours.
Last year, the $2.3bn (USD$1.5bn) telescope’s first test images showed an incredible array of stars and galaxies taken from Lagrange point 2 – a fixed position 1.5m kilometres in Earth’s shadow, next to the Gaia and James Webb space telescopes.
