Is it globular clusters or is it globeular clusters? It doesn’t matter, they’re awesome and we’re here to update you on them.
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Fraser calls them “globe-ular” clusters, and Pamela calls them “glob-ular” clusters. Both are correct.
Where are the Intermediate black holes?
Shapley–Sawyer Concentration Class
Dark globular cluster
Metallicity – the population of heavier elements as metals and to the proportions of these elements.
NGC 2808 contains three distinct generations of stars.
Djorgovski 1’s stars contain hydrogen and helium, but not much else.
Two populations of globular clusters, which became known as Oosterhoff groups:
type I are referred to as “metal-rich” (for example, Terzan 7)
Type 2 have lightly longer period of RR Lyrae variable stars, but are “metal-poor” (for example, ESO 280-SC06)
Exotic classes of stars, such as blue stragglers, millisecond pulsars and low-mass X-ray binaries, are much more common in globular clusters.