The cosmic “dark ages” that followed the Big Bang ended when the first stars illuminated the universe during the cosmic dawn. However, one of the great unsolved mysteries of the universe is how its mass is distributed.
Mathematical reproductions of the development of the main stars gauge that the mass of the principal stars reached up to a few hundred sun-based masses. Among them, pair-instability supernovae (PISNe) were the first stars with masses between 140 and 260 solar masses. PISNe are very different from customary supernovae (i.e., Type II and Type Ia supernovae) and would have engraved a special synthetic mark in the environment of the cutting-edge stars. But no such signature has been discovered.
Based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey and follow-up high-resolution spectra observed by Subaru Telescope, a new study led by Prof. Zhao Gang from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) has identified a chemically peculiar star (LAMOST J1010+2358) in the galactic halo as clear evidence of the existence of PISNe from very massive first stars in the gas cloud dominated by the yields of a PISN with 260 solar masses.
“It provides an important clue to constraining the initial mass function in the early universe. Prior to this study, no evidence of supernovae from such massive stars had been found in metal-poor stars.”
Prof. Zhao Gang, corresponding author of the study.
The group likewise incorporates scientists from Yunnan Observatories of CAS, the Public Cosmic Observatory of Japan, and Monash College, Australia.
This study was distributed online in Nature.
The examination group has performed follow-as-high as possible goal spectroscopic perception for J1010+2358 with the Subaru telescope and inferred overflows for in excess of ten components. The main component of this star is its incredibly low sodium and cobalt overflows. Its sodium-to-press proportion is lower than 1/100 of the sun’s power. In addition, elements with odd and even charge numbers, such as sodium/magnesium and cobalt/nickel, have very different abundances in this star.
Examination of noticed overflows and models The compound overflows of J1010+2358 contrast with the forecasts from three hypothetical cosmic explosion models. The observed abundances’ uncertainties are represented by error bars of one sigma. Credit: NAOC
Dr. Xing Qianfan, the study’s first author, stated, “The peculiar odd-even variance, along with deficiencies of sodium and elements in this star, are consistent with the prediction of primordial PISN from first-generation stars with 260 solar masses.”
According to the theory of very massive star evolution, the hydrodynamical instability caused by the production of electron-positron pairs is directly demonstrated by the discovery of J1010+2358. The formation of electron-positron pairs results in a partial collapse and a decrease in the thermal pressure that exists within the core of a very massive star.
Prof. Zhao Gang, the study’s corresponding author, said, “It provides an essential clue to constraining the initial mass function in the early universe.” Before this review, no proof of supernovae from such gigantic stars had been found in the metal-unfortunate stars.”
Additionally, the fact that LAMOST J1010+2358 has a much higher iron abundance than the majority of the galactic halo’s metal-poor stars ([Fe/H] = -2.42) suggests that the second-generation stars formed in the PISN-dominated gas may be more metal-rich than anticipated.
“One of the sacred goals of looking for metal-unfortunate stars is to find proof for these early pair-precariousness supernovae,” said Prof. Avi Loeb, previous chair of the Stargazing Division at Harvard College.
“This paper presents what is, to my knowledge, the first definitive association of a galactic halo star with an abundance pattern originating from a PISN,” said Prof. Timothy Beers, the provost’s chair of astrophysics at Notre Dame University.
More information: Zhao Gang et al, A metal-poor star with abundances from a pair instability supernova, Nature (2023). DOI: 10.1038/s41586-023-06028-1, https://www.nature.com/articles/s41586-023-06028-1
