Scientists find unusually small stars that could help explain the mysteries of the galaxy

In the binary named Mira, a red giant star transfers mass to a white dwarf. (NASA/CXC/M.WEISS)

Scientists have found unusually “slim” red giants – a new kind of star that could explain some of the mysteries of our galaxy.

There are millions of red giants littered throughout our Milky Way. They offer a look at the future of our solar system: in another four billion or so years, our Sun will become one of those cool and luminous objects that surround us.

But scientists have long thought there could be slimmer versions of them around too. Now they have been able to finally confirm their existence.

“It’s like finding Waldo,” said lead author Yaguang Li from the University of Sydney.

“We were extremely lucky to find about 40 slimmer red giants, hidden in a sea of normal ones. The slimmer red giants are either smaller in size or less massive than normal red giants.”

Scientists are still not sure how the strange little stars got to be so small. But most stars are in binary systems – where two stars are bound to each other by gravity – and the small stars have likely lost some of their material as a result.

“In the case of relatively tiny red giants, we think a companion could possibly be present,” Mr Li said.