Astronomers Observe Peanut Shell-Shaped Galaxies For The First Time


With specially designed software, Australian astronomers have discovered something peculiar recently: peanut shell-shaped structures in galaxies, which may help explain how ours developed.

A peanut shell within a peanut shell - this aptly describes the structure astronomers from the Swinburne University of Technology in Melbourne have seen while studying two disc galaxies, NGC 128 and NGC 2549, using information from the Sloan Digital Sky Survey and Hubble Space Telescope.

"Peanut shells" observed actually referred to the distribution of billions of stars within these galaxies that are bulging, becoming more apparent because these galaxies tend to have flattened discs.

This type of structure is also not uncommon as we have one in the Milky Way, but what makes this one unique is the fact that there seems to be two layers, with one appearing faint and found inside the other.

"This is the first time such a phenomenon has been observed," said Bogdan Ciambur, lead investigator.

How Could This Happen?

It may have something to do with the shape of the stars' distribution, which may look like bars. To recreate the same double peanut shell patterns, these disc galaxies should contain two of these bars with each of the ends of the bars bending.

"The instability mechanism may be similar to water running through a garden hose. When the water pressure is low, the hose remains still - the stars stay on their usual orbits. But when the pressure is high the hose starts to bend - stellar orbits bend outside of the disc," said Ciambur.

Since the discovery is truly odd, there's still a lot of work to do, but the astronomers think this may be useful in helping us understand how our very own peanut shell works. It may even provide a glimpse into the past, including how their and our galaxies formed.

This isn't the first time, though, that astronomers have found something different in the universe. The Newfound Blob, formed by massive gas bubbles, is approximately 11 billion light-years away from us, making it one of the oldest and the farthest.

NASA has also treated us recently with a time-lapse video of the core of the Milky Way galaxy with images captured for four years until 2014.

The study can now be read in Monthly Notices of the Royal Astronomical Society.

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