From the 1 of 4 linked papers with an AI index.
4 papers
The Twentieth Data Release of the Sloan Digital Sky Survey: First All-Sky BOSS Spectra, eROSITA-SDSS-V Mapper Coordinated Observations, and a Preview of the Local Volume Mapper
SDSS Collaboration, Mojgan Aghakhanloo, David Aguilar +273
The paper describes the twentieth data release (DR20) of the Sloan Digital Sky Survey, providing over 3 million new optical spectra from the SDSS‑V Milky Way, Black Hole, and Local…
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…
[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…
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…