Embarking on a cosmic journey, recent research has shed light on the distinctive shape of the stellar halo, a diffuse cloud of stars that surrounds the disk of our galaxy. Contrary to the previous assumption of a spherical formation reminiscent of a beach ball, the latest findings portray our stellar halo more like a tilted, rectangular football. This groundbreaking research, published in The Astronomical Journal, opens new doors to understanding the evolution of our galaxy and provides critical clues in the pursuit of the elusive dark matter.
The stellar halo of the Milky Way is a visible segment of the broader galactic halo. This vast halo is governed by invisible dark matter, whose existence is inferred through the gravitational force it exerts - a phenomenon common to all galaxies. However, understanding the shape of our own stellar halo has posed a formidable challenge to astronomers, primarily because our viewpoint is from within this vast structure.
The stellar halo extends hundreds of thousands of light years above and below our galaxy's star-strewn plane, the home of our Solar System. The latest study, conducted by astronomers at the Center for Astrophysics (CfA) and their colleagues, employs two extensive datasets collected over the years to study the stellar halo with unprecedented detail.
By integrating these datasets into a flexible model, the researchers allowed the actual shape of the stellar halo to emerge from their analysis. The result? A decidedly non-spherical halo, resembling a kicked football [2]. This intriguing shape aligns with other research to date and has significant implications for understanding the past interactions between our galaxy and the Gaia-Enceladus-Sausage (GSE) dwarf galaxy.
The peculiar shape of the stellar halo provides a window into those astronomical events that occurred billions of years ago. It points towards the presence of two pileups of stars in the stellar halo, likely formed during GSE's two orbits of the Milky Way. This triaxial ellipsoid shape, as it is technically known, is a testament to the dynamic and turbulent history of our galaxy.
This research not only offers a deeper understanding of our galaxy's past but also provides valuable insights into the properties and distribution of dark matter. As Earth travels through the Milky Way, it periodically encounters regions rich in high-velocity dark matter particles, enhancing the chances of their detection.
The unveiling of the most probable shape of the stellar halo propels astronomical research forward, offering crucial insights into our place in the universe [2]. This pioneering study is a significant step towards unraveling the mysteries of the cosmos, enhancing our knowledge of our galaxy's past, present, and future.
Reference: SciTechDaily
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