the stars in the Milky Way," said coauthor Puragra Guhathakurta, professor of astronomy and astrophysics at UC Santa Cruz.
Researchers said finding the stars was meticulous work. Each Hubble image contained more than 100,000 stars.
"We had to somehow find those few stars that actually belonged to the Milky Way halo. It was like finding needles in a haystack," Marel said.