An an unusual “break” has been detected in the nearest galactic spiral arm towards the Earth. Astronomers have never seen anything like it and are not entirely sure how it got there.
New research published in Astronomy & Astrophysics describes a “high pitch angle structure in Sagittarius armBy “high pitch,” astronomers refer to the extreme angle at which this elongated cluster of stars emerges. the Sagittarius arm of the Milky Way. The newly detected function measures 3,000 lightyears of duration (that is, less than 3% of the total diameter of the entire galaxy), and consists of young stars and gas clouds that form stars. Caltech astrophysicist Michael Kuhn is the lead author of the study.
Mapping the various features of our galaxy is not easy, and that is because we live directly within the thing. As the new article says, “it has been a challenge to connect individual star-forming regions to their larger galactic environment because of our perspective from the disk.”
Fortunately, astronomical tools and techniques can help in this regard. In this case, Kuhn and colleagues analyzed the data collected by Spitzer Space Telescope, which NASA withdrew just last year. Spitzer detected infrared light, making it an ideal tool for observing newborn stars that would be covered by thick clouds of gas and dust (i.e., nebulae) from which they formed. Specifically, the team examined data from a survey called the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), in which Spitzer scanned more than 100,000 star babies.
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Data from the European Space Agency’s Gaia mission, which provided the team with accurate measurements of distances between stars, were also analyzed. This allowed them to create a 3D view of the Sagittarius arm, a prominent spiral arm of the Milky Way galaxy.
“When we put together the Gaia and Spitzer data and finally look at this detailed three-dimensional map, we can see that there is quite a bit of complexity in this region that had not been seen before,” Kuhn said at a NASA Press release.
He The Sagittarius arm is a well-studied feature of the Milky Way and is home to several giant star-forming regions, including the Omega Nebula, the Trifid Nebula, the Lagoon Nebula, and the Eagle Nebula, which contains the famous Pillars of creation. For the new study, researchers attempted to map the locations and velocities of star-forming regions in a segment of the Sagittarius arm.
The new structure detected is left out with a step angle of almost 60 degrees. The same arm wraps tightly around the Milky Way with a 12-degree step angle (by context, a perfect circle has a 0-degree step angle). Hence the description of the chip as a high-pass angle structure.
“Ultimately, this reminds us that there are a lot of uncertainties about the large-scale structure of the Milky Way, and we need to look at the details if we want to understand this broader picture,” said Robert Benjamin, an astrophysicist at the University of Wisconsin. -Whitewater and principal investigator of GLIMPSE.
The authors of the new paper are not entirely sure how the split works formed, but the baby stars within this extension probably existed at the same time and place. As closely related siblings, these stars should have been affected by the same influences caused by the rotation of the galaxy: forces such as gravity and shear. Thus, improved star models, both in terms of their distance from each other and their speed, could shed light on this new astronomical mystery. and galactic spirals in general, which are also mysterious.
“This structure is a small piece of the Milky Way, but it could tell us something significant about the Galaxy as a whole,” Benjamin said.
Astronomers have previously observed odd ball shots in other spiral galaxies, including things called spurs and feathers, some of which protrude perpendicularly from the spiral arms. Spurs are bright spots caused by the abundance of stars, while feathers are conglomerations of dust. The new feature seen in the Milky Way is none of these and is therefore considered unique.
It is now an open question about whether other high-pass angle structures exist in our galaxy or anywhere else in the universe. This will be the focus of future work, along with further research to confirm the new feature as a good faith substructure with the Sagittarius arm.
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