Astronomers lately mapped the rarest sort of galaxy ever discovered: an elliptical galaxy sporting rings of younger stars.
Most galaxies, together with our personal Milky Approach, are spiral or elliptical. However this lately mapped galaxy, referred to as PGC 1000714, is exclusive. Situated about 359 million light-years from Earth, it has two rings: an outer ring and an internal ring. The rings are made up of largely younger stars, whereas the core is made from older, redder stars, researchers reported in a brand new examine describing the findings.
“The completely different colours of the internal and outer ring recommend that this galaxy has skilled two completely different formation durations,” lead examine writer Burcin Mutlu-Pakdil, a graduate pupil on the College of Minnesota Duluth, mentioned in a press release. “From these preliminary single snapshots in time, it is unattainable to know the way the rings of this explicit galaxy have been fashioned.” [65 Awesome Galaxy Photos to Behold]
The internal ring seems older than its outer counterpart, examine co-author Patrick Treuthardt, an astrophysicist on the North Carolina Museum of Pure Sciences, mentioned within the assertion.
Such “ring” galaxies are often known as Hoag-type galaxies in honor of astronomer Artwork Hoag, who found a prototypical instance of the galaxy sort in 1950. Solely zero.1 % of galaxies ever noticed are Hoag-type galaxies, Mutlu-Pakdil mentioned.
Present theories recommend that Hoag-type galaxies type when two galaxies collide and the everyday spiral arm construction is disrupted, the researchers mentioned. That leaves a hoop of gasoline, mud and stars slowly spreading outward, just like ripples in a pond.
It is doable that the outer ring was fashioned when PGC 1000714 absorbed a smaller galaxy, whereas the older, internal ring was created in another manner, the researchers mentioned. Nevertheless, to know for positive, researchers should catalog many different galaxies prefer it.
“Each time we discover a distinctive or unusual object to check, it challenges our present theories and assumptions about how the universe works,” Treuthardt mentioned. “It normally tells us that we nonetheless have quite a bit to study.”
The examine was detailed on-line Nov. 30 within the journal Month-to-month Notices of the Royal Astronomical Society.