p class= »sc-77igqf-0 bOfvBY »>Une Unusual ‘break’ detected in nearest galaxy spiral arm towards Earth. Astronomers have never seen anything like it, and they don’t really know how it got there.
New research published in Astronomy & Astrophysics describes a “high pitch angle structure in the Sagittarius arm. By “high height”, astronomers refer to the extreme angle at which this elongated star cluster protrudes by. the Sagittarius arm of the Milky Way. Newly detected function measures 3000 light-years in length (that’s less than 3% of the total diameter of the entire galaxy), and it is made up of young stars and star-forming gas clouds. Caltech astrophysicist Michael Kuhn is the lead author of the study.
Mapping the different characteristics of our galaxy isn’t easy, and that’s because we live directly inside it. As the new article says, “It has been difficult to connect individual star-forming regions to their larger galactic environment due to our perspective from inside the disk.”
Fortunately, astronomical tools and techniques can help in this regard. In this case, Kuhn and his colleagues analyzed data collected by the Spitzer Space Telescope, which NASA withdrew last year. Spitzer detected infrared light, making it an ideal tool for observing newly born stars that would otherwise be covered by the thick clouds of gas and dust (i.e. nebulae) from which they were formed. Specifically, the team looked at data from a survey called the Galactic Legacy Infrared Mid-Plane Survey Extraordinary (GLIMPSE), in which Spitzer scanned more than 100,000 baby stars.
Data from the European Space Agency’s Gaia mission was also analyzed, providing the team with precise measurements of the distances between stars. This allowed them to create a 3D view of the Sagittarius arm, a prominent spiral arm in the Milky Way galaxy.
“When we put the Gaia and Spitzer data together and finally see this detailed three-dimensional map, we can see that there’s a little bit of complexity in this region that just wasn’t apparent before,” Kuhn said in a NASA press release. Press release.
The The Sagittarius arm is a well-studied feature of the Milky Way and is home to several regions of gigantic star formation, including the Omega Nebula, the Trifid Nebula, the Lagoon Nebula, and the Eagle Nebula, the latter containing the popular Pillars of creation. For the new study, the researchers sought to map the locations and velocities of regions of star formation in a segment of the Sagittarius arm.
Newly detected structure pops out at a tilt angle of almost 60 degrees. The arm itself wraps tightly around the Milky Way at a pitch angle of 12 degrees (for context, a perfect circle has a pitch angle of 0 degrees). Hence the description of the shard as a wide angle pitch structure.
“Ultimately, this is a reminder that there are many uncertainties around the large-scale structure of the Milky Way, and we need to look at the details if we are to understand this larger picture,” explained Robert Benjamin, an astrophysicist at the ‘University. from Wisconsin-Whitewater and Principal Investigator for GLIMPSE.
The authors of the new article are not entirely sure how the shine formed, but the star babies in this expanse likely were born at the same time and in the same 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 models of stars, both in terms of distances between them and speeds, 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 important about the Galaxy as a whole,” Benjamin said.
Astronomers have observed characteristics of odd balls in other spiral galaxies in the past, including things called spurs and feathers, some of which protrude perpendicularly from the spiral arms. Spurs are bright spots caused by an abundance of stars, while feathers are conglomerates of dust. The new functionality seen in the Milky Way is neither and is therefore considered unique.
It is now an open question whether other wide pitch angle structures exist in our galaxy or elsewhere in the universe. This will be the subject of future work, as well as further research to confirm the new functionality as a bona fide substructure with the Sagittarius arm.
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