Chinese astronomers detect 9 super lithium-rich unevolved stars

BEIJING, July 5 (Xinhua) -- Using China's largest optical telescope, astronomers have discovered a record number of unevolved stars rich in lithium, a key chemical element linking cosmology to the structure and evolution of stars.

With the help of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), a team led by researchers from the National Astronomical Observatories under the Chinese Academy of Sciences has discovered nine new lithium-rich unevolved stars, more than twice as many as previously known. The study was published in The Astrophysical Journal Letters.

LAMOST at Xinglong Station of National Astronomical Observatory in north China's Hebei Province. (Photo: CFP)

Researchers wrote in the paper that the newfound stars present unusually high levels of lithium abundances, which suggests that they must have experienced a history of lithium enrichment.

According to the study, the lithium contents of the nine stars are about three times higher than the lithium content of the sun. Given that seven of the stars are fast rotators, the astronomers assume that the accretion of circumstellar matter may be the main contributor to the stars' lithium enhancement.

Although the mechanisms of lithium enrichment in the unevolved stars have been discussed widely, they remain unclear. The detection of the nine new stars of this class could be a breakthrough in the field, the researchers noted in a statement on Tuesday.

LAMOST went into operation in 2008 to collect high-quality spectra, data collection that helps astronomers study celestial bodies' chemical composition, density, atmosphere and magnetism. The telescope has helped scientists discover the heaviest stellar black hole and the most lithium-rich giant star.

Further studies are necessary in order to confirm these discoveries. The researchers said that sky surveys by LAMOST will yield further discoveries of super lithium-rich unevolved stars.