One of the Oldest Stars in the Universe Discovered in Earth's Backyard

Tuesday, 06 November 2018 - 12:10PM
Astronomy
Science News
Tuesday, 06 November 2018 - 12:10PM
One of the Oldest Stars in the Universe Discovered in Earth's Backyard
< >
ESO/Beletsky/DSS1 + DSS2 + 2MASS CC BY 4.0
Science Alert reports a team of astronomers have discovered a little star in the Milky Way Galaxy believed to be around 13.5 billion years old, which would make it one of the oldest in the Universe. Given the lengthy designation 2MASS J18082002–5104378 B, the star is only about 10 percent the mass of our Sun, but don't confuse size with importance.

In research soon to be published in The Astrophysical Journal, the astronomers discuss how the star was found: 2MASS J18082002–5104378 B is very small and not very bright. While studying its binary companion, the team noticed the faint motion of the star. A spectroscopic analysis showed that 2MASS is very low in metal-at around 10 percent of Earth's metal content, it has the lowest metallicity of any star ever discovered. As Science Alert explains, there were no metals in the early Universe, and each generation of stars formed after the Big Bang grows in metallicity.

"This discovery tells us that the very first stars in the Universe didn't have to all be massive stars that died long ago," Monash University astrophysicist Andrew Casey told the science publication. "These ancient stars could form from very small amounts of material, which means some of those relics from soon after the Big Bang could still exist today. That gives us a new viewpoint for star formation in the early Universe!"

According to Casey, the discovery of 2MASS could help change how astronomers think about the formation of the Universe and cause a shift in which stars get all the attention based on their size. "The problem is that astronomers have long-believed that the first stars in the Universe were massive, and therefore none of them should survive until the present day. This discovery helps change all that: it shows that ancient stars can be very low mass, which implies that some of the oldest stars in the Universe may still be around today." On the possibility of finding more of 2MASS's ancient brothers and sisters in the Milky Way, the astronomer said that the star is "extremely rare" but championed the idea of continuing the search, because "with huge amounts of data from ground-based and space-based telescopes, the future looks good: we are closer than ever to understanding how stars formed in the early Universe."

Cover photo: ESO/Beletsky/DSS1 + DSS2 + 2MASS CC BY 4.0
Science
Space
Astronomy
Science News
No