A new study has focused on the spectra of NGC 6652 obtained by the Cerro Tololo Observatory and found that the globular cluster NGC 6652.4.05957 is 13.6 billion years old. This makes the cluster one of the oldest objects in the Milky Way.
What’s more, scientists also found that the metallicity of this cluster is relatively high because of its unusual dynamics – the matter which formed the cluster has passed through the galactic disk multiple times and amassed the heavy elements synthesized there.
Globular clusters are mostly situated tens and hundreds of thousands of light-years from Earth, and only the brightest stars in them can be studied. Margarita Sharina, a Kazan Federal University alumna, came up with the idea of researching the spectra of full star clusters several years ago.
Along with Associate Professor Vladislav Shimansky (Kazan Federal University), she developed Cluster, a special software package to model such spectra. During their joint work, the two scientists have determined fundamental characteristics of almost 40 globular clusters.
In this study, scientists analyzed the spectra of NGC 6652. They found that the overall ratio of heavy elements in the cluster turned out to be unusually high.
Shimansky said, “For a long time, the consensus was that the younger the galactic object is, the higher its metallicity. Closer to the late 20th century, astronomers started to move away from this viewpoint.”