Hubble scientists find new way to measure age of star clusters

This image of Hubble shows a scene in the confines of our galactic neighbor, the galaxy of the Great Magellanic Cloud (LMC). This object, called NGC 1466, is a type of star group called a globular group – a group of stars that are held together by gravity and that move together across the edges of the LMC. It is located 160 000 light years from Earth. Together, NGC 1466 weighs the equivalent of 140,000 of our sun and is extremely old. Scientists calculate that it is 13.1 billion years old, which is almost as old as the universe itself.

The object however provides more than a beautiful image. Hubble's observations have revealed in more detail how star clusters are formed and developed. Since star clusters are active and evolving, with structures changing over time, larger and heavier stars tend to sink towards the middle of the cluster. Over time, the core of cluster contracts.

However, there is something strange about the stellar cluster of CML. The youngest groups are compact, while the older groups come in both compact and diffuse forms. New research suggests that this can be understood by looking at a type of "invigorated star" called a blue retarder. These stars collect excess fuel when they travel and become considerably brighter. And because they have high masses, latecomers are drawn to the center of the clusters.

This means that astronomers are able to observe the blue stragglers in the clusters of CML and use these observations to rank the clusters in order of age. "We have shown that the different structures of star clusters are due to different levels of dynamic aging: they have different physical forms even though they are born at the same cosmic moment," Francesco Ferraro explained. University of Bologna in Italy. declaration. "This is the first time that the effect of dynamic aging has been measured in the LMC clusters."

In the same statement, Barbara Lanzoni, co-author, said in one statement: "These results offer interesting lines of research, as they reveal a new and valuable way to read the observed patterns of LMC star clusters. , providing new insights into the history of cluster formation in the LMC galaxy. "

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