6 papers
TESS Asteroseismology of Red Giants in the Old Metal-Rich Open Clusters NGC 188 & NGC 6791
Madeline Howell, Jennifer A. Johnson, Marc H. Pinsonneault +5
Open clusters are fundamental laboratories for investigating stellar and Galactic evolution, and serve as important benchmarks for asteroseismic analyses. Using a boutique method t…
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 and Extra-Mixing for [Fe/H] <- 0.5: Insights from the LMC and SMC
Yuxi Lu, John D. Roberts, Joshua T. Povick +4
The [C/N]-age relation has become a powerful tool for reconstructing the formation history of the Milky Way (MW), providing the largest age sample for field giant stars. However, a…
Checking It Twice: Using [C/N]-Masses and Asteroseismic Masses as a Diagnostic of Mass Loss and Transfer on the RGB
John D. Roberts, Marc H. Pinsonneault, Jennifer A. Johnson +1
The surface [C/N] of red giants is correlated with birth mass, but not directly impacted by mass loss. Exploiting this, we compare asteroseismic masses of red giants with the same…
[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…
Anchoring Stellar Age Indicators: A Cross-Calibration of [C/N] and Gyrochronology Ages via the Age-Velocity-Dispersion Relation
Yuxi Lu, Marc H. Pinsonneault, Yuan-Sen Ting +4
Determining stellar ages is challenging, as it depends on other stellar parameters in a non-linear way and often relies on stellar evolution models to infer the underlying relation…