Chemical Evolution in the Milky Way: Rotation-based Ages for APOGEE-Kepler Cool Dwarf Stars

Claytor, Zachary R.; van Saders, Jennifer L.; Santos, Ângela R. G.; García, Rafael A.; Mathur, Savita; Tayar, Jamie; Pinsonneault, Marc H.; Shetrone, Matthew
Bibliographical reference

The Astrophysical Journal

Advertised on:
Number of authors
IAC number of authors
Refereed citations
We use models of stellar angular momentum evolution to determine ages for ∼500 stars in the APOGEE-Kepler Cool Dwarfs sample. We focus on lower-main-sequence stars, where other age-dating tools become ineffective. Our age distributions are compared to those derived from asteroseismic and giant samples and solar analogs. We are able to recover gyrochronological ages for old, lower-main-sequence stars, a remarkable improvement over prior work in hotter stars. Under our model assumptions, our ages have a median relative uncertainty of 14%, comparable to the age precision inferred for more massive stars using traditional methods. We investigate trends of Galactic α-enhancement with age, finding evidence of a detection threshold between the age of the oldest α-poor stars and that of the bulk α-rich population. We argue that gyrochronology is an effective tool reaching ages of 10─12 Gyr in K and early M dwarfs. Finally, we present the first effort to quantify the impact of detailed abundance patterns on rotational evolution. We estimate a ∼15% bias in age for cool, α-enhanced (+0.4 dex) stars when standard solar-abundance-pattern rotational models are used for age inference, rather than models that appropriately account for α-enrichment.
Related projects
Helio and Asteroseismology
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary