README.md

February 11, 2026 · View on GitHub

istary

Center for Cosmology and AstroParticle Physics (CCAPP)

Department of Astronomy, The Ohio State University

18 December 2025

All isochrone sample tables were computed using the YREC Code and Sample Grid. Pre-made Isochrones can be found in the Isochrones File.

Note that for the isochrone creation to work, user may need to stitch the files together so they are not broken by the evolutionary phase. Relevant code is provided in YREC_isochrones_guide_final.ipynb. When running this notebook, if using the pre-made grid use the YREC_grids_sample.zip files to load the .*eep.pkl or .*interpolator.pkl files. Further instructions on loading the grid are in the .ipynb guide outlined below.

Isochrones were made using the code in YREC_isochrones_guide_final.ipynb found in the yrec_user_tools repository, or here. Isochrone EEPs were generated using a wrapper function employing the Kiauhoku Stellar Model Interpolator from Claytor et al., 2020.

While the library is currently limited, more cases will be generated over time.

Isochrone Library Parameters:

M/H (Z/X) = 0
Ages: 100Myr to 900Myr & from 1.0 Gyr to 14.0 Gyr
M67, the Pleiades, the Hyades, and Praesepe are also modeled

Namesake From Istari:

The Wizards or Istari in J. R. R. Tolkien's fiction were powerful angelic beings, Maiar, who took the physical form and some of the limitations of Men to intervene in the affairs of Middle-earth in the Third Age, after catastrophically violent direct interventions by the Valar, and indeed by the one god Eru Ilúvatar, in the earlier ages.

Wizards like Gandalf were immortal Maiar, but took the form of Men. Two Wizards, Gandalf the Grey and Saruman the White, largely represent the order, though a third Wizard, Radagast the Brown, appears briefly. Two Blue Wizards are mentioned in passing.