MADISON, Wis., Dec. 28 (UPI) -- Ancient bright stars known as "blue stragglers" likely increase their mass by stealing fuel from companion stars, astronomers in Wisconsin said.
"These blue, luminous stars should have used up their hydrogen fuel and flamed out long ago. Yet they are still here," said Robert Mathieu, an astronomer with the University of Wisconsin, Madison.
Blue stragglers likely gain mass by crashing into nearby stars, a theory once thought far-fetched by astronomers, Mathieu and his university colleague, Aaron Geller, said in a recent issue of the journal Nature.
Many astronomers now believe binary star systems containing blue stragglers brush against one another on collision-course orbits, said Mathieu and Geller, who based their observations by studying an old star cluster called NGC 188, located 6,000 light years from Earth.
NGC 188, located near Polaris, the North Star, has 21 blue stragglers among its several thousand other stars.
"What blue stragglers are showing us is that life in a star cluster is rarely a lonely existence," Mathieu said.
