A new image taken with the NASA/ESA Hubble Space Telescope provides a detailed look at NGC 2210, a globular cluster situated in the Large Magellanic Cloud.
This Hubble image shows NGC 2210, a globular cluster located 163,000 light-years away in the constellation of Dorado. Also known as ESO 57-71 or LW 423, the cluster was first discovered on January 31, 1835 by the English astronomer John Herschel. The color image is made up of observations from Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) and in the ultraviolet, near-infrared, and optical parts of the spectrum. It is based on data obtained through three filters. The color results from assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA / ESA / Hubble / A. Sarajedini / F. Niederhofer.
Globular clusters are systems of very ancient stars, gravitationally bound into a single structure about 100-200 light-years across.
They contain hundreds of thousands or perhaps a million stars. The large mass in the rich stellar center of a cluster pulls the stars inward to form a ball of stars.
Globular clusters are among the oldest known objects in the Universe and are relics of the first epochs of galaxy formation.
It is thought that every galaxy has a population of globular clusters.
Our Milky Way Galaxy hosts at least 150 such objects and a few more are likely to exist hidden behind the Galaxy’s thick disk.
The Large Magellanic Cloud, a neighboring dwarf galaxy about 163,000 light-years away from us, is home to approximately 60 globular clusters.
In 2017, University of Florida astronomer Rachel Wagner-Kaiser and her colleagues revealed that six ancient globular clusters in the Large Magellanic Cloud — NGC 1466, NGC 1841, NGC 2210, NGC 2257, Hodge 11 and Reticulum — were incredibly close in age to some of the oldest stellar clusters found in the Milky Way’s halo.
They found that NGC 2210 specifically probably clocks in at around 11.6 billion years of age.
Even though this is only a couple of billion years younger than the Universe itself, it made NGC 2210 by far the youngest globular cluster in their sample.
All other globular clusters studied in the work were found to be even older, with four of them over 13 billion years old.
“This is interesting, because it tells us that the oldest globular clusters in the Large Magellanic Cloud formed contemporaneously with the oldest clusters in the Milky Way, even though the two galaxies formed independently,” the researchers said.
“As well as being a source of interesting research, this old-but-relatively-young cluster is also extremely beautiful, with its highly concentrated population of stars.”
“The night sky would look very different from the perspective of an inhabitant of a planet orbiting one of the stars in a globular cluster’s center: the sky would appear to be stuffed full of stars, in a stellar environment that is thousands of times more crowded than our own.”
_____
R. Wagner-Kaiser et al. 2017. Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud – II. Relative ages and distances for six ancient globular clusters. MNRAS 471 (3): 3347-3358; doi: 10.1093/mnras/stx1702