One of the arms of the Milky Way Galaxy seen from Patagonia, Argentina. (Image credit: Natapong Supalertsophon/Getty Images) Our home galaxy didn't pop into existence all at once. The Milky Way was formed gradually, as smaller galaxies, or dwarf galaxies, were subsumed into our own galaxy over billions of years. It turns out that the stars leftover from these dwarf galaxies still share characteristics, and scientists are getting better at identifying them. By studying their similarities, scientists use these stars to determine their galaxies of origin. A team of astronomers say that they have identified a sample of these 20 stars that — due to their similar features — may have grown up together in a dwarf galaxy which the researchers have dubbed "Loki." "We might have detected one of the various small systems that contributed to form our Milky Way," astronomer Federico Sestito, a postdoctoral fellow at University of Hertfordshire and study coauthor, told Space.com via email.…