For the first time! Chinese scientists discovered the chemical remains of the first generation of supermassive stars

(Original title: Appointment with the Starry Sky丨Scientists discover chemical remains of the first generation of supermassive stars for the first time)

An artistic representation of the evolution of the first generation of supermassive stars into unstable supernovae. (Photo courtesy of the National Astronomical Observatory of the Chinese Academy of Sciences)

Using the Guo Shoujing Telescope, scientists discovered the chemical remains of a first-generation star with a mass of 260 times that of the sun among the stars in the galactic halo. This is the first observational confirmation of the theoretical conjecture that the mass of the first-generation stars can reach hundreds of times that of the sun, which is of great significance for further exploring the mysteries of cosmic evolution.

The research was completed by an international team led by Zhao Gang, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, and the relevant results were published online in the international academic journal Nature on the 7th.

Guo Shoujing Telescope. (Photo courtesy of the National Astronomical Observatories of the Chinese Academy of Sciences)

After the Big Bang, the first generation of stars formed. They not only brought the first ray of light to the universe, but also created new elements, dominating the chemical enrichment process and evolutionary history of the early universe.

"Since the first generation of stars were born a long time ago and had a short lifespan, it is extremely difficult to observe them directly now, so research is mainly carried out through extremely metal-poor stars. Some extremely metal-poor stars may be born in the gas clouds formed at the end of the first generation of stars, and are the 'living fossils' for studying the first generation of stars." The first author of the article, Xing Qianfan, an associate researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, introduced that astronomical theory speculates that the mass of the first generation of stars can reach hundreds of times the mass of the sun, but before this, the first generation of supermassive stars with more than 100 times the mass of the sun have never been confirmed by observation.

In this study, the team combined the low-resolution spectrum data of the Guo Shoujing Telescope and the high-resolution spectrum data of the Subaru Telescope in Japan to discover an extremely metal-poor star with extremely special chemical abundance (LAMOST J1010+2358). The chemical abundance characteristics of this star cannot be explained by the core-collapse supernova theoretical model, but are highly consistent with the theoretical calculation results of a pair-instability supernova of 260 times the mass of the sun.

Comparison of the chemical abundance of the peculiar star LAMOST J1010+2358 with the supernova model. (Photo courtesy of the National Astronomical Observatory of the Chinese Academy of Sciences)

Reviewers of the journal Nature commented that this discovery provided decisive evidence for the first time for the connection between unstable supernovae and the chemical abundance of stars in the Milky Way halo. In the future, the analysis of the remains of the first generation of stars can deepen our understanding of the evolutionary history of the Milky Way.

"This work is of great significance to the study of the initial mass function of the first generation of stars, and will have a profound impact on the study of the origin of elements, star formation in the early universe, and chemical evolution of galaxies," said Zhao Gang. (Reporter Zhang Quan)