You might be surprised at the bright disc full of stars you call home if you step out of the Milky Way. It has a strange warp to it. It seems that the rest of our galaxy is also a bit off-kilter.
A new map of the stars above and below the galactic plane shows its galactic halo – the diffuse globe of gas, dark matter, and stars that surrounds spiral galaxies – is also wonky. The halo of the Milky Way is not the smooth, round sphere that astronomers had expected. Instead, it’s a wibbly ellipsoid with three axes that are all different lengths.
“For decades, it has been assumed that the stellar halo is more spherical, isotropic, or the exact same in all directions. says astronomer Charlie Conroy of the Harvard & Smithsonian Center for Astrophysics (CfA).
“We now understand that the traditional picture of our galaxy inscribed within a volume of stars is wrong.”
It’s not easy to figure out the shape and size of our galaxy. Imagine trying to determine the shape of a large lake while floating around in it. We have only recently gained an in-depth understanding of the three-dimensional structure of our galaxy thanks to the Gaia telescope launched by the European Space Agency in 2013.
Gaia orbits the Sun in the same orbit as Earth. It can measure the Solar System’s changes in position by moving the telescope. parallaxThe Milky Way contains many objects that can be measured to determine the movements and positions of thousands of distant stars.
We now know the location of the Milky Way’s disc thanks to this data Bending and warping. We also know that we have seen the Milky Way engage in numerous occasions. Galactic cannibalismOne of the most striking examples of this seems to be a collision with the galaxy we call the Gaia SausageGaia Enceladus or, was around 7-10 billion years ago.
Scientists believe that this collision took place. Starry halo created by the Milkyway. As it approached our galaxy, the Gaia Sausage broke apart, with its distinctive population of stars scattered through the Milky Way’s cloud.
Jiwon Han, an astronomer and PhD student at CfA, led a group of scientists to better understand the galactic halo.
“The stellar halo acts as a tracer for the galactic halo.” Han. The stellar halo can be a great place for learning about galactic and interstellar haloes, as well as our galaxy’s galactic history and galactic Haloes.
Gaia’s data about the chemical abundances beyond certain distances of halo star stars is not reliable. The chemical abundances of halo stars can tie together stellar populations, which is important information to map the relationship between them.
Researchers added data from Hectochelle to the Halo at High Resolution. H3; A ground-based survey that collected chemical abundance data for thousands of stars in Milky Way’s stellar halo.
These data allowed the researchers to infer the density profile of stars within the Milky Way’s Milky Way halo. Their data best fit was a football-shaped, tilted 25° with respect to the galactic plane.
This is compatible with previous studiesIt was found that the Milky Way’s stars were located in a triaxial ellipsoid structure (although details vary slightly). It is consistent with the theory of the Gaia sausage creating or playing a major role in the creation of the Milky Way halo. The halo’s skewiff shape indicates that the galaxies collided at an angled angle.
Researchers also discovered two star pileups at significant distances away from the galactic centre. These collections, they found, represent the apocenters of the initial stellar orbits around the galactic center – the farthest distance the stars travel in their elongated, elliptical orbits.
As an orbiting body Speeds upOn The point nearest to the center of attraction (or ‘pericenter”)The apocenter is a place of slow-down. When the Gaia Sausage met with the Milky Way, its stars were flung out into two wild orbits, slowing down at the apocenters – to the point of stopping, and just making that location their new home.
But this was very long ago. Long enough that the strange shape should have resolved itself long before it settled back into an sphere. The strong tilt suggests that the halo of dark matter binding the Milky Way – a mysterious mass responsible for excess gravity in the Universe – is also highly tilted.
We have exciting new questions, and we do have some exciting new answers. Future and ongoing surveys, according to researchers, will provide more precise constraints on the shape the halo, which should help us understand the evolution of our galaxy.
“These are some of the most interesting and intuitively fascinating questions we can ask about our galaxy. “What is the starry halo like?”‘,” Han:.
“With this particular line of research and study, we finally answer those questions.”
The research was published in The Astronomical Journal.
