Our home galaxy, the Milky Way, makes for a pretty space image, and it’s normal at a distance. but new 3D map reveals a surprise: The milky way is being warped and twisted by its stars.
The Milky Way is a spiral galaxy, in which stars and gas clouds exist mainly in its 2 spiral “arms.” Our massive neighbour, the Andromeda galaxy, is also a spiral.
Spiral galaxies usually seem very flat and easy to see through a telescope, said the researchers behind the new map, revealed Monday in the journal Nature astronomy.
By Using 1,339 large, pulsating stars to compile a 3D map of the Milky Way, researchers discovered instead that the galaxy’s disk of stars is increasingly twisting, most likely due to the spinning of the disk.
And the farther the stars are from the centre, the more twisted it becomes.
The stars used to create the map are known as classical Cepheids. These are young stars, between four and twenty times the mass of our sun and 100,000 times brighter.
Given their mass and brightness, they probably burn through their fuel quickly and die after a few million years — young for the lifespan of a star.
Last time, astronomers saw evidence of hydrogen clouds becoming warped in the Milky Way.
This isn’t completely abnormal, because astronomers have noticed the same pattern of progressively twisting spirals in about a dozen different galaxies.
But it does help them make more sense of our galaxy.Because we live in this galaxy, that makes it harder to observe, and dust and starlight make it even tougher when using telescopes.
Trying to determine what our galactic centre appears like is similar to trying to find the centre of a forest you are standing in.
It is notoriously difficult to determine distances from the Sun to parts of the milky Way’s outer gas disc without having a clear idea of what that disc actually appears like, lead study author Xiaodian Chen of Chinese academy of sciences in Beijing said in a statement.
From afar, the Milky Way seems like a thin rotating disk of stars, orbiting the centre each few hundred million years.
In the centre, hundreds of billions of stars and dark matter hold the galaxy together. however as you move toward the outermost reaches of the galaxy, the gravitational glue of the centre fades.
In the outer disk, this keeps hydrogen gas from being confined, that contributes to an s-shaped warping.
Some what to our surprise we found that in 3D our collection of 1339 Cepheid stars and the Milky Way’s gas disk follow each other closely. This gives new insights into the formation of our home galaxy, Richard DE Grijs, senior study author and professor at Macquarie University’s Department of Physics and astronomy, said in a statement.
“Perhaps more importantly, in the milky Way’s outer regions, we found that the S-like stellar disk is warped in a progressively twisted spiral pattern.
So the huge inner disk’s rotational force causes the outer disk to warp, the researchers concluded. This research provides a vital updated map for studies of our galaxy’s stellar motions and the origins of the Milky Way’s disk, said Licai Deng, author and senior researcher at Chinese academy of sciences, in a statement.