The Milky Way galaxy has a barred spiral shape, with arms of stars, gas and dust winding out from a central bar. Viewed from the side, the Galaxy would appear relatively flat, with most of the material in a disc and the central regions.
Stars form inside massive and dense clumps of gas in so-called giant molecular clouds (GMCs) that are mainly located in the inner part of the galactic disc.
With many clumps in a single GMC, most (if not all) stars are born together in clusters.
They not only found GMCs thousands of light years above and below the galactic disc, but that one of them unexpectedly contained two clusters of stars.
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This is the first time astronomers have found stars being born in such a remote location.
The new clusters, named Camargo 438 and 439, are within the molecular cloud HRK 81.4-77.8.
This cloud is thought to be about 2 million years old and is around 16,000 light years beneath the galactic disk, an enormous distance away from the usual regions of star formation, in the direction of the constellation of Cetus.
The other idea is that the interaction between our Galaxy and its satellites, the Magellanic Clouds, may have disturbed gas that falls into the Galaxy, again leading to the creation of GMCs and stars.
"Our work shows that the space around the Galaxy is a lot less empty that we thought. The new clusters of stars are truly exotic," Denilso said.
"Now we want to understand how the ingredients for making stars made it to such a distant spot. We need more data and some serious work on computer models to try to answer this question," he said.
The research is published in the journal Monthly Notices of the Royal Astronomical Society.