Research Reveals The Birthplace Of Gold Rich Stars

A team of researchers from the University of Notre Dame and Tohoku University have revealed the birthplace of so-called “gold-rich” stars – stars with an abundance of heavy elements beyond iron, including the “jewellery elements”, gold and platinum. Their research is published in Monthly Notices of the Royal Astronomical Society. Hundreds of gold-rich stars have been discovered by state-of-the-art telescopes around the world. The mystery was when, where and how these stars formed in the history of the Milky Way, the galaxy in which we live. The team found that most of the gold-rich stars formed in the Milky Way’s small progenitor galaxies 10 billion years ago, shedding light on the stars’ past for the first time. To reach this conclusion, the team traced the formation of the Galaxy from the Big Bang to the present day with a numerical simulation. This simulation has the highest temporal resolution achieved to date—it can accurately resolve the cycle of star-forming materials in our Galaxy. The simulation was created over several months using the ATERUI II supercomputer at the Center for Computational Science at the National Astronomical Observatory of Japan. The simulation made it possible to analyze the formation of gold-rich stars in our Galaxy for the first time. The standard cosmology he used predicts that the Milky Way grows by the accretion and merger of small progenitor galaxies. The simulation data revealed that some of the progenitor galaxies – which existed more than 10 billion years ago – contained large amounts of the heavier elements. Each neutron star merger event—a confirmed site of heavy element nucleation—increased the abundance of the heavier elements in these small galaxies. Gold-rich stars formed in these galaxies, and their predicted abundances can be compared to observations of stars today. Yutaka Hirai, of Tohoku University, says: “Gold-rich stars today tell us the story of our Galaxy—we found that most gold-rich stars formed in dwarf galaxies more than 10 billion years ago. These ancient galaxies are the building blocks of the Galaxy. Our findings mean that many of the gold-rich stars we see today are the fossils of our Galaxy’s formation more than 10 billion years ago.” He adds, “Comparison with simulations and observations in the Milky Way opens a new avenue for deriving the fossil record of stars.” The research appears as “Neutron star mergers as the astrophysical location of the r process in the Milky Way and its satellite galaxies,” published in Monthly Notices of the Royal Astronomical Society. More information: Yutaka Hirai et al, Origin of highly r-process enhanced stars in a cosmological zoom-in simulation of a Milky Way-like galaxy, Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac2489 Provided by the Royal Astronomical Society Reference: Survey reveals birthplace of gold-rich stars (2022 November 14) Retrieved November 14, 2022 by This document is subject to copyright. Except for any fair dealing for purposes of private study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.

title: “Research Reveals The Birthplace Of Gold Rich Stars " ShowToc: true date: “2022-11-15” author: “Penelope Jones”

A team of researchers from the University of Notre Dame and Tohoku University have revealed the birthplace of so-called “gold-rich” stars – stars with an abundance of heavy elements beyond iron, including the “jewellery elements”, gold and platinum. Their research is published in Monthly Notices of the Royal Astronomical Society. Hundreds of gold-rich stars have been discovered by state-of-the-art telescopes around the world. The mystery was when, where and how these stars formed in the history of the Milky Way, the galaxy in which we live. The team found that most of the gold-rich stars formed in the Milky Way’s small progenitor galaxies 10 billion years ago, shedding light on the stars’ past for the first time. To reach this conclusion, the team traced the formation of the Galaxy from the Big Bang to the present day with a numerical simulation. This simulation has the highest temporal resolution achieved to date—it can accurately resolve the cycle of star-forming materials in our Galaxy. The simulation was created over several months using the ATERUI II supercomputer at the Center for Computational Science at the National Astronomical Observatory of Japan. The simulation made it possible to analyze the formation of gold-rich stars in our Galaxy for the first time. The standard cosmology he used predicts that the Milky Way grows by the accretion and merger of small progenitor galaxies. The simulation data revealed that some of the progenitor galaxies – which existed more than 10 billion years ago – contained large amounts of the heavier elements. Each neutron star merger event—a confirmed site of heavy element nucleation—increased the abundance of the heavier elements in these small galaxies. Gold-rich stars formed in these galaxies, and their predicted abundances can be compared to observations of stars today. Yutaka Hirai, of Tohoku University, says: “Gold-rich stars today tell us the story of our Galaxy—we found that most gold-rich stars formed in dwarf galaxies more than 10 billion years ago. These ancient galaxies are the building blocks of the Galaxy. Our findings mean that many of the gold-rich stars we see today are the fossils of our Galaxy’s formation more than 10 billion years ago.” He adds, “Comparison with simulations and observations in the Milky Way opens a new avenue for deriving the fossil record of stars.” The research appears as “Neutron star mergers as the astrophysical location of the r process in the Milky Way and its satellite galaxies,” published in Monthly Notices of the Royal Astronomical Society. More information: Yutaka Hirai et al, Origin of highly r-process enhanced stars in a cosmological zoom-in simulation of a Milky Way-like galaxy, Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac2489 Provided by the Royal Astronomical Society Reference: Survey reveals birthplace of gold-rich stars (2022 November 14) Retrieved November 14, 2022 by This document is subject to copyright. Except for any fair dealing for purposes of private study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.