New extremely r-process-enhanced star detected

Astronomers at the Chinese Academy of Sciences (CAS) and elsewhere have used the Grand Telescope of Canarias (GTC) to discover a new star in the thin disk of the Milky Way galaxy that exhibits a highly pronounced r-process. They report the discovery in a research paper. Published July 16th Preprint Server arXiv.

R-process enhanced (RPE) stars are a very small fraction of old stars. Metal-poor starsshow a significant enrichment of elements (e.g. europium, thorium, uranium) produced by rapid neutron capture processes. These stars reside mainly in the Galactic halo and in dwarf satellite galaxies of the Milky Way, and are excellent laboratories for studying the r-process, which may help us better understand the formation history of galaxies.

now, Astronomer A research team led by Xiao-Jin Xie of CAS reported the detection of a new RPE star. They used GTC’s High Resolution Spectrograph (HORuS) to observe the star, which they named LAMOST J020623.21+494127.9 (or J 0206+4941 for short). Observation campaign This object was classified as a star with a highly enhanced r-process.

“that [J 0206+4941] “This star was originally selected as a candidate RPE star from the LAMOST medium-resolution survey based on unusually strong lines of europium,” the researchers wrote in their paper.

Observations have revealed that J 0206+4941 is a bright star that belongs to the thin disk of the Milky Way galaxy. Based on the collected data, astronomers managed to derive the abundances of 30 elements of this star and determine its kinematics.

The new findings suggest that J 0206+4941 has a metallicity of -0.54. Effective Temperature The temperature is about 4,078 K, and the abundance ratio of europium to hydrogen is 0.78. In general, the light element abundances of this star are comparable to other stars of similar metallicity and evolutionary stage, with a large enrichment of europium and a moderate enrichment of barium.

The authors of the paper emphasized that J 0206+4941 is the most metal-rich star ever discovered, with a significantly enhanced r-process. The age of the star is unknown, but is probably around 12.3 billion years, although further studies are needed to confirm this.

In an attempt to explain the origin of J 0206+4941, scientists have not ruled out the possibility that it was born in situ in the thin disk of the Milky Way. They say it Interstellar matter (ISM) is enriched in r-process elements by a single binary neutron star merger or core-collapse supernova (CCSNe).

In conclusion, the astronomers noted that in addition to J 0206+4941, they have also identified several metal-rich RPE candidates that are worthy of further investigation using instruments such as HORuS.

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