Chinese astronomers discover giant star rich in lithium

BEIJING - Chinese astronomers have discovered the most lithium-rich giant star ever known, which could shed new light on the evolution of the universe.

With 3,000 times more lithium than a normal star, it was found in the direction of Ophiuchus, on the north side of the galactic disk, at a distance of 4,500 light years from Earth.

A research team, led by astronomers from National Astronomical Observatories of China (NAOC) of the Chinese Academy of Sciences, made the discovery with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), a special quasi-meridian reflecting Schmidt telescope located in NAOC's Xinglong Observatory, in north China's Hebei Province.

The telescope can observe about 4,000 celestial bodies at one time and has made a massive contribution to the study of the structure of the galaxy.

Lithium is considered one of the three elements synthesized in the Big Bang, together with hydrogen and helium. The abundance of the three elements was regarded as the strongest evidence of the Big Bang.

The evolution of lithium has been a key subject in the research of the evolution of the universe and stars. However, giant stars rich in lithium are very rare, with only a few found over the past three decades. This makes their study remarkably challenging, said Zhao Gang, a lead astronomer at NAOC.

"The discovery of this star has largely increased the upper limit of observed lithium abundance," said Zhao.

The newly discovered star has a mass almost 1.5 times our sun. Details of the star were obtained by follow-up observation through the Automated Planet Finder telescope at Lick Observatory in the United States.

Scientists from other institutions, including the China Institute of Atomic Energy and Beijing Normal University, joined the team and helped discern a possible explanation for the lithium-rich phenomenon through a nuclear network simulation with the latest atomic data.

The researchers believe the abundant lithium might be a result of a special material exchange process in the interior of the star.

Finished in 2008, LAMOST began regular surveys in 2012. It has helped Chinese scientists with a final catalog of about 10 million spectra over six years and established the world's largest databank of stellar spectra.

The results of the study were published in the latest issue of Nature Astronomy.