Astronomers observing the massive, ovular Centaurus A galaxy noticed several globular star clusters floating around it.
According to Discovery News, the Centarus A large elliptical galaxy scientifically named NGC 5128 is the closest one to the Milky Way at 12 million light years. Globular star clusters are collections of stars that band together and orbit galaxies.
The researchers' work is published in the Astrophysical Journal.
"Globular clusters and their constituent stars are keys to understanding the formation and evolution of galaxies," study lead author Matt Taylor, a PhD student at the Pontificia Universidad Catolica de Chile in Santiago, Chile, said in a press release. "For decades, astronomers thought that the stars that made up a given globular cluster all shared the same ages and chemical compositions - but we now know that they are stranger and more complicated creatures."
Taylor and his team made their observations using the European Southern Observatory's (ESO) Very Large Telescope at the Paranal Observatory in Chile.
"Our discovery of star clusters with unexpectedly high masses for the amount of stars they contain hints that there might be multiple families of globular clusters, with differing formation histories," study co-author Thomas Puzia, a Pontificia Universidad colleague of Taylor's, said in the release. "Apparently some star clusters look like, walk like, and smell like run-of-the-mill globulars, but there may quite literally be more to them than meets the eye."
The researchers estimated some 2,000 globular clusters to be orbiting Centaurus A, surveying 125 of them.
"We have stumbled on a new and mysterious class of star cluster," Taylor said. "This shows that we still have much to learn about all aspects of globular cluster formation. It's an important result and we now need to find further examples of dark clusters around other galaxies."
