A group 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 Method’s outer limits.
In line with the researchers, these 208 stars are situated within the farthest components of the Milky Method’s halo, a spherical stellar cloud that’s dominated by the mysterious darkish matter, which is invisible and might solely be detected by its gravitational results. The furthest of them is 1.08 million light-years from Earth.
So how lengthy wouldn’t it 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 could take about 1.6 million years to journey 100 gentle years.
These stars belong to the category of stars often known as RR Lyrae. These are comparatively low-mass stars with restricted quantities of parts heavier than hydrogen and helium. They have been found with the Canada-France-Hawaii telescope on Hawaii’s Mauna Kea mountain. Probably the most distant star seems to be 70% of the mass of our Solar.
The celebs that make up the galactic halo’s periphery may be considered stellar orphans; they seemingly got here from smaller galaxies that later collided with the larger Milky Method.
“Our interpretation concerning the origin of those distant stars is that they’re more than likely born within the halos of dwarf galaxies and star clusters which have been later merged – or extra straightforwardly, cannibalized – by the Milky Method,” stated Yuting Feng, a College 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, however these stars are left at that giant distance as particles of the merger occasion,” Feng added.
The Milky Method has expanded over time, via such catastrophes.
“The bigger galaxy grows by consuming smaller galaxies – by consuming its personal type,” stated examine co-author Raja GuhaThakurta, UC Santa Cruz’s chair of astronomy and astrophysics.
The Milky Method’s halo, which has an interior and outer layer, is way larger than the galaxy’s essential 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 Method’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.
