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Y 2 Isochrones with an Improved Core Overshoot Treatment
Convective core overshoot affects stellar evolution rates and the dating of stellar populations. In this paper, we provide a patch to the Y2 isochrones with an improved treatment of convective core
Toward Better Age Estimates for Stellar Populations: The Y2 Isochrones for Solar Mixture
We have constructed a new set of isochrones, called the Y2 Isochrones, that represent an update of the Revised Yale Isochrones (RYI), using improved opacities and equations of state. Helium diffusion
The YY Isochrones for alpha-element Enhanced Mixtures
We present a new set of isochrones in which the effect of the alpha-element enhancement is fully incorporated. These isochrones are an extension of the already published set of YY Isochrones (Yi et
The Current State of Solar Modeling
Data from the GONG project and other helioseismic experiments reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone, which is plausible that the sound-speed differences reflect weak mixing in stellar interiors.
NGC 6791: An Exotic Open Cluster or the Nucleus of a Tidally Disrupted Galaxy?
We report on high-resolution echelle spectroscopy of 20 giant stars in the Galactic old open cluster NGC 6791, obtained with Hydra at the WIYN telescope. High-precision radial velocity allows us to
The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem?
We review five independent techniques that are used to set the distance scale to globular clusters, including subdwarf main-sequence fitting utilizing the recent Hipparcos parallax catalog. These
The Y2 Stellar Evolutionary Tracks
We present a database of the latest stellar models of the Y2 (Yonsei-Yale) collaboration. This database contains the stellar evolutionary tracks from the pre-main-sequence birthline to the helium
Standard solar model
A set of solar models have been constructed, each based on a single modification to the physics of a reference solar model. In addition, a model combining several of the improvements has been
WIYN Open Cluster Study. II. UBVRI CCD Photometry of the Open Cluster NGC 188
We present high-precision UBVRI CCD photometry of the old open cluster NGC 188. Our color-magnitude diagram extends from near the red giant branch tip to as faint as ~5 mag below the main-sequence
Evolutionary models of the rotating sun
This paper reviews current work on the evolution of a differentially rotating solar model. Although we discuss global features of the evolution with rotation in general terms, the specific models