Stellar fossil: imprints of pair instability supernovae from extremely massive first stars. Credit: NAOC
Researchers from the Chinese Academy of Sciences and global partners have discovered a star, LAMOST J1010 +2358, that supplies the very first tangible proof of Pair-Instability Supernovae (PISNe) from deep spaces earliest stars. This finding, published in Nature, sheds light on the advancement of massive stars and the early Universes preliminary mass function.
The very first stars illuminated the Universe throughout the Cosmic Dawn and put an end to the cosmic “dark ages” that followed the Big Bang. However, the distribution of their mass is among the great unsolved mysteries of the universes.
Mathematical simulations of the development of the first stars estimate that the mass of the first stars reached up to numerous hundred solar masses. Among them, the first stars with masses in between 140 and 260 solar masses ended up as pair-instability supernovae (PISNe).
A new research study led by Prof. Gang Zhao from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) has determined 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 early Universe, based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey and follow-up high-resolution spectra observation by Subaru Telescope. It has been validated that this star was formed in the gas cloud controlled by the yields of a PISN with 260 solar masses.
The group also consists of scientists from Yunnan Observatories of CAS, National Astronomical Observatory of Japan, and Monash University, Australia.
This study will be published online in Nature today (June 7, 2023).
The chemical abundances of J1010 +2358 compared with the predictions from three theoretical supernova designs. The error bars are 1 sigma uncertainties of the observed abundances.
The most considerable feature of this star is its incredibly low salt and cobalt abundances. This star also shows a really big abundance variation in between the odd and even charge number aspects, such as sodium/magnesium and cobalt/nickel.
” The peculiar odd-even difference, together with deficiencies of salt and α-elements in this star, follow the forecast of primitive PISN from first-generation stars with 260 solar masses,” stated Dr. Qianfan Xing, first author of the study.
The discovery of J1010 +2358 is direct evidence of the hydrodynamical instability due to electron– positron pair production in the theory of extremely enormous star evolution. The development of electron– positron pairs minimizes thermal pressure inside the core of a really enormous star and results in a partial collapse.
” It offers a necessary idea to constraining the initial mass function in the early universe,” stated Prof. Gang Zhao, corresponding author of the study. “Before this study, no proof of supernovae from such massive stars has been discovered in the metal-poor stars.”
The iron abundance of LAMOST J1010 +2358 ([ Fe/H] = -2.42) is much higher than the most metal-poor stars in the Galactic halo, suggesting that the second-generation stars formed in the PISN-dominated gas may be more metal-rich than expected.
” One of the holy grails of looking for metal-poor stars is to find evidence for these early pair-instability supernovae,” said Prof. Avi Loeb, former chair of the Astronomy Department at Harvard University.
Prof. Timothy Beers, the provosts chair of astrophysics at Notre Dame University, discussed the outcomes: “This paper provides what is, to my knowledge, the first definitive association of a Galactic halo star with an abundance pattern stemming from a PISN.”
Referral: “A metal-poor star with abundances from a set instability supernova” 7 June 2023, Nature.DOI: 10.1038/ s41586-023-06028-1.
Numerical simulations of the development of the first stars approximate that the mass of the very first stars reached up to numerous hundred solar masses. Among them, the very first stars with masses between 140 and 260 solar masses ended up as pair-instability supernovae (PISNe). PISNe are quite various from ordinary supernovae (i.e., Type II and Type Ia supernovae) and would have inscribed a special chemical signature in the environment of the next-generation stars. The most substantial feature of this star is its very low sodium and cobalt abundances. = -2.42) is much greater than the most metal-poor stars in the Galactic halo, recommending that the second-generation stars formed in the PISN-dominated gas may be more metal-rich than anticipated.
