Astronomers Spot Most Lithium-Rich Star In The Whole Galaxy
Chinese astronomers have managed to locate the most lithium-rich star in the Milky Way, the national media outlet Xinhua announced earlier this week.
The star in question, a red giant found 4,500 light-years away from Earth, has an extremely high lithium abundance — 3,000 times higher than a typical red giant star, reports Phys.org.
Dubbed TYC 429-2097-1, this unusual star lies in the Ophiuchus constellation (the “Serpent Bearer,” symbolized by a man clutching a snake) and seems to be at the beginning of its lithium-rich phase, shows a new study detailing the discovery.
The credit for this amazing find belongs to scientists from the National Astronomical Observatories of China (NAOC) of the Chinese Academy of Sciences in Beijing, who spotted the lithium-rich star with the help of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).
Housed in NAOC’s Xinglong Observatory, in the Hebei Province of north China, LAMOST is a special quasi-meridian reflecting Schmidt telescope able to observe nearly 4,000 celestial bodies in one swoop.
According to the new study, recently published in the journal Nature, around 1 percent of the giant stars in the Milky Way have “anomalously high lithium abundances in their atmospheres.” These objects contradict the predictions of standard stellar evolution models, throwing astronomers for a loop.
“Decades of effort have been put into explaining why such extreme objects exist, yet the origins of lithium-rich giants are still being debated,” the authors wrote in their paper.
The newly discovered star is the most lithium-rich known to date. Only a handful of such stars have been detected in the past 30 years, notes Tech2.
“The discovery of this star has largely increased the upper limit of the observed lithium abundance, and provides a potential explanation to the extremely lithium-rich case,” said Prof. Zhao Gang, senior author of the new paper.
After LAMOST picked up the red giant in its field of view, the researchers studied the star with the Automated Planet Finder (APF) telescope at Lick Observatory in California and believe they have found an answer as to why TYC 429-2097-1 has such a high abundance of lithium.
The team suggests that this low-mass star, just 1.5 times more massive than the sun, was able to generate this incredible amount of lithium “through the transportation of beryllium during the red giant phase,” explains the paper. The astronomers detail their hypothesis in a nuclear simulation model presented in the study and which recreates the process that filled up the red giant with so much lithium.
Another intriguing thing about TYC 429-2097-1 is that the star was found to be on the red-giant-branch, the interval of stellar evolution before helium ignition occurs.
“Such a high lithium abundance indicates that the star might be at the very beginning of its lithium-rich phase, which provides a great opportunity to investigate the origin and evolution of lithium in the galaxy,” the authors wrote in the study.
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