3 papers
astro-ph.SR2025
[C/N] Ages for Red Giants and their Implications for Galactic Archaeology
John D. Roberts, Marc H. Pinsonneault, Jennifer A. Johnson +2
Red giants undergo the first dredge-up, a mixing event that creates a connection between their surface [C/N] and their mass and age. We derive a [C/N]-Age relationship for red gian…
astro-ph.GA2025
Challenges to the Two-Infall Scenario by Large Stellar Age Catalogs
Liam O. Dubay, Jennifer A. Johnson, James W. Johnson +1
Stars in the Milky Way disk exhibit a clear separation into two chemically distinct populations based on their [/Fe] ratios. This -bimodality is not a universal feature of si…
astro-ph.GA2024
The Milky Way Radial Metallicity Gradient as an Equilibrium Phenomenon: Why Old Stars are Metal-Rich
James W. Johnson, David H. Weinberg, Guillermo A. Blanc +12
Metallicities of both gas and stars decline toward large radii in spiral galaxies, a trend known as the radial metallicity gradient. We quantify the evolution of the metallicity gr…