Skip to main content
  1. Home
  2. Space
  3. News

Hubble scientists find new way to measure the age of star clusters

By
This image from the NASA/ESA Hubble Space Telescope reveals an ancient, glimmering ball of stars called NGC 1466. ESA/Hubble & NASA

This Hubble image shows a scene within the bounds of our galactic neighbor, the Large Magellanic Cloud (LMC) galaxy. This particular object, called NGC 1466, is a type of star cluster called a globular cluster — a group of stars that are held together by gravity and which move together through the edges of the LMC. It is located 160,000 light-years away from Earth. Together, NGC 1466 weighs the equivalent of 140,000 of our Sun and is extremely old. Scientists calculate it is 13.1 billion years old, which is nearly as old as the universe itself.

The object provides more than just a pretty picture, however. Observations from Hubble have revealed more about how star clusters form and grow. Because star clusters are active and evolving, with structures that change over time, larger and heavier stars tend to sink towards the middle of the cluster. Over time, the core of the cluster contracts.

Recommended Videos

However, there’s something odd about the star clusters in the LMC. The younger clusters are compact, while older clusters come in both compact and diffuse forms. The new research suggests this can be understood by looking at a type of “re-invigorated star” called a blue straggler. These stars collect extra fuel as they travel and become significantly brighter. And because they have high masses, the stragglers are pulled to the center of clusters.

Related

This means that astronomers are able to observe blue stragglers in LMC clusters and use these observations to rank the clusters in order of age. “We demonstrated that different structures of star clusters are due to different levels of dynamical aging: they are in different physical shape despite the fact that they were born at the same cosmic time,” Francesco Ferraro of the University of Bologna in Italy explained in a statement. “This is the first time that the effect of dynamical aging has been measured in the LMC clusters.”

This data could be useful for future research as well, co-author Barbara Lanzoni said in the same statement: “These findings present intriguing areas for further research, since they reveal a novel and valuable way of reading the observed patterns of LMC star clusters, providing new hints about the cluster formation history in the LMC galaxy.”

Editors' Recommendations

Topics
Georgina Torbet
Georgina Torbet
Space Writer
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
A sparkling field of stars cluster together in Hubble image
This image shows just a portion of M55, the cluster as a whole appears spherical because the stars’ intense gravitational attraction pulls them together. Hubble’s clear view above Earth’s atmosphere resolves individual stars in this cluster. Ground-based telescopes can also resolve individual stars in M55, but fewer stars are visible.

A sea of stars sparkles in this image from the Hubble Space Telescope. Showing an tremendous cluster of stars called a globular cluster, this view is located in the galaxy Messier 55.

A globular cluster is a group of stars which is tens of thousands or even millions of stars, and which is held together by gravity. That's why these clusters tend to form spherical shapes as the forces of gravity hold the cluster together.

Read more
An enormous galaxy cluster warps spacetime in this Hubble image
A massive galaxy cluster in the constellation Cetus dominates the centre of this image from the NASA/ESA Hubble Space Telescope. This image is populated with a serene collection of elliptical and spiral galaxies, but galaxies surrounding the central cluster — which is named SPT-CL J0019-2026 — appear stretched into bright arcs, as if distorted by a gargantuan magnifying glass. This cosmic contortion is called gravitational lensing, and it occurs when a massive object like a galaxy cluster has a sufficiently powerful gravitational field to distort and magnify the light from background objects.

Every week, scientists using the Hubble Space Telescope share an image from this beloved piece of space technology, and this week's image shows a vital astronomical phenomenon in action. While space telescopes can observe very far-off objects if they are bright enough, there is still a lot of the universe that is too far away to observe -- which is why researchers make use of a natural occurrence called gravitational lensing.

Gravitational lensing happens when an object like a galaxy or galaxy cluster has so much mass that it noticeably warps spacetime. Everything with mass bends spacetime somewhat, but usually this effect is so small as to be effectively invisible. But when the object is something with as much mass as a large galaxy or even a collection of galaxies, then this warping can be significant enough for us to observe it.

Read more
Hubble measures the mass of a lonely dead star for the first time
A single bright blue star dominates the scene against a dark background with many small stars visible in the distance.

In billions of years' time, after our sun has burned through all of its fuel and puffed up to be a red giant, it will eventually shrink and cool until all that remains is the dense core of the former star, called a white dwarf. This is what will eventually happen to most stars, so white dwarfs are common in the universe. But there is much we still have to learn about these core remnants, and recent research using the Hubble Space Telescope has measured the mass of a lone white dwarf for the first time.

Previously, the mass of white dwarfs was measured when they were a part of a binary. When two stars orbit each other, astronomers can figure out their masses. However, there are also many single white dwarfs out there and it was difficult to work out their mass.

Read more