The extremely metal- poorer galaxy, nicknamed Peekaboo, emerged out of a fast-moving star relatively recently.
The Hubble Space Telescope (HST) has helped astronomers confirm that a nearby dwarf galaxy is seriously lacking in the heavy elements, a trait generally observed in galaxies in the distant, early universe.
While galaxies evolve, multiple generations of stars produce elements heavier than hydrogen and helium, enriching the universe with what astronomers collectively call metals. Nevertheless, astronomers state this curious galaxy is “extremely metal-poor” – an unanticipated find for a galaxy a mere 20 million light-years away.
“At initially we didn’t recognize how special this small galaxy is,” said Bärbel Koribalski, an astronomer at Australia ‘s coauthor and CSIRO of a recently available study on the galaxy, in a NASA news release. “Now with combined data from the Hubble Space Telescope, the Southern African Large Telescope (SALT), and some, we understand that the Peekaboo Galaxy is one of the most metal poor galaxies ever detected.”
Spectroscopic data captured by SALT additionally indicates the little galaxy’s stars just began developing within the last billion years or so, which could allow it to be among the youngest galaxies in our cosmic area yet discovered.
The Peekaboo Galaxy
At only 1,200 light years throughout – when compared with the Milky Way’s nearly 100,000-light-year width – the dwarf galaxy is formally known as HIPASS J1131-31. Astronomers gave it the name “Peekaboo” since it first appeared in the past 50 to 100 years from behind a fast moving star.
Very metal-poor galaxies such as Peekaboo aren’t unusual by any stretch of the significance. Astronomers, though, generally discover them in the first universe. This’s because the first galaxies and consequently the first stars were nearly completely composed of helium and hydrogen. They got enhanced with heavy elements as decades of massive stars exploded as supernovae and ejected their metal innards.
“Uncovering the Peekaboo Galaxy is like finding an immediate window into the past, enabling us to study its extreme surroundings and stars at a level of detail that’s unavailable in the distant, early universe,” said astronomer Gagandeep Anand of the Space Telescope Science Institute as well as coauthor of the new study.
As a part of its snapshot – Survey program known as The Every Known Nearby Galaxy survey, Hubble was able to resolve approximately 60 stars in Peekaboo. The team hopes to get further observations of Peekaboo’s stars down the road using Hubble and the James Webb Space Telescope.
“Because of Peekaboo’s proximity to us, we can do detailed observations, opening up possibilities of seeing a planet similar to the early universe in unprecedented detail,” said Anand.
The results were published Nov. 12 in Monthly Notices of the Royal Astronomical Society.