Astronomers recently discovered a rare type of galaxy, one with an elliptical core surrounded by two rings.
Hoag-type galaxies are extremely rare. The center of these galaxies contain ancient cores (5.5 billion years old) and are comprised mainly of older stars, while the outer ring is filled with young stars aged around 130 million years old. What’s unique about Hoag-type galaxies is their apparent method of formation; this new discovery shows that a galaxy of this type may have two different formation periods.
“The different colors of the inner and outer ring suggest that this galaxy has experienced two different formation periods. From these initial single snapshots in time, it’s impossible to know how the rings of this particular galaxy were formed.” –
– Burcin Mutlu-Pakdil, University of Minnesota Duluth
It’s suspected that the outer ring formed by cannibalizing the gasses of another nearby galaxy in it’s formation period. The inner disk’s formation still eludes scientists and researchers; higher resolution images are needed to make necessary observations of the phenomena.
“Whenever we find a unique or strange object to study, it challenges our current theories and assumptions about how the Universe works. It usually tells us that we still have a lot to learn.”
– Patrick Treuthardt, North Carolina Museum of Natural Science
Hoag-type galaxies make up less than 0.1 percent of all observed galaxies in our universe. Findings from this article were published in the Monthly Notices of the Royal Astronomical Society.
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