A set of stars which might be farther away from Earth than any beforehand recognized inside our personal galaxy – practically midway to a neighboring galaxy – have been discovered within the stellar halo that represents the Milky Way’s outer limits.
According to the researchers, these 208 stars are situated within the farthest components of the Milky Way’s halo, a spherical stellar cloud that’s dominated by the mysterious darkish matter, which is invisible and may solely be detected by its gravitational results. The furthest of them is 1.08 million light-years from Earth.
So how lengthy would it not take to journey 100 gentle years?
A lightweight yr is the gap gentle travels in a yr, 5.9 trillion miles (9.5 trillion km). So it will take about 1.6 million years to journey 100 gentle years.
These stars belong to the category of stars generally known as RR Lyrae. These are comparatively low-mass stars with restricted quantities of components heavier than hydrogen and helium. They had been found with the Canada-France-Hawaii telescope on Hawaii’s Mauna Kea mountain. The most distant star seems to be 70% of the mass of our Sun.
The stars that make up the galactic halo’s periphery will be considered stellar orphans; they seemingly got here from smaller galaxies that later collided with the larger Milky Way.
“Our interpretation about the origin of these distant stars is that they are most likely born in the halos of dwarf galaxies and star clusters which were later merged – or more straightforwardly, cannibalized – by the Milky Way,” stated Yuting Feng, a University of California, Santa Cruz PhD scholar in astronomy, led the examine and introduced it this week at an American Astronomical Society assembly in Seattle.
“Their host galaxies have been gravitationally shredded and digested, but these stars are left at that large distance as debris of the merger event,” Feng added.
The Milky Way has expanded over time, by way of such catastrophes.
“The larger galaxy grows by eating smaller galaxies – by eating its own kind,” stated examine co-author Raja GuhaThakurta, UC Santa Cruz’s chair of astronomy and astrophysics.
The Milky Way’s halo, which has an interior and outer layer, is much greater than the galaxy’s primary disk and core bulge, that are teeming with stars. Our solar, which is situated in one of many 4 principal spiral arms that make up the Milky Way’s disk, is among the many 100 billion to 400 billion stars that make up the galaxy, which has a supermassive black gap at its middle situated round 26,000 gentle years from Earth. About 5% of the celebrities within the galaxy are discovered within the halo.