The discovery of several large, metal-poor stars located far from the center of the Andromeda galaxy suggests our nearest galactic neighbour might be up to five times larger than previously thought. The newfound stars are massive, bloated stars known as red giants. Although found far beyond the most visible portion of Andromeda’s swirling disk, the stars are still gravitationally bound to the galaxy and make up part of its extended „halo“. The finding, presented on Sunday at the 209th meeting of the American Astronomical Society, suggests Andromeda is at least one million light-years across and could help settle a discrepancy between Andromeda and the Milky Way that has long puzzled astronomers.
Astronomers discover an enormous halo of red giant stars around Andromeda