ASTR-502

Repository for ASTR 502 stellar isochrone interpolation, single-target fitting, and batch catalog fitting workflows.

Repository structure

data/
  raw/
    catalogs/
      ASTR502_Mega_Target_List.csv
      ASTR502_Master_Photometry_List.csv
      k2_star_ages.csv
      kepler_star_ages.csv
    isochrones/
      MIST/
      SPOTS/

outputs/
  logs/               # timestamped interpolation logs
  results/            # fit result CSV outputs
  figs/               # generated diagnostic plots

src/astr502/
  domain/
    schemas.py        # fit-result schemas
    stats.py          # chi-square and residual terms
  data/
    paths.py          # canonical repo/data/output paths
    catalogs.py       # catalog loading + priors + observed magnitudes
    utils.py          # logging + SPOT helpers
    readers/
      read_spot_models.py
      read_mist_models.py
  modeling/
    extinction.py     # extinction by band
    interpolate.py    # interpolation grid + optimization (+ optional emcee)
  services/
    fit_runtime.py    # single-target + batch runtime wrappers
    plots.py          # observed-vs-table age scatter plotting
    gyro.py           # compare fitted ages against Kepler ages
    regress.py        # linear regression of interpolated vs Kepler ages

scripts/
  fit_single_star.py  # CLI wrapper for one hostname
  fit_target_list.py  # CLI wrapper for full/subset target-list runs
  fetch_iso.py        # ezpadova isochrone fetching/plot helper classes
  find_mag.py         # photometry + distance merge helper class

Setup

Install dependencies:

pip install -r requirements.txt

CLI scripts

1) Fit a single star

python scripts/fit_single_star.py [--mega-csv PATH] [--phot-csv PATH] [--output-csv PATH] [--av-min 0.0] [--av-max 3.0] [--quiet]

Notes:

• The script currently prompts interactively for hostname (Hostname:).
• Default catalog paths are data/raw/catalogs/ASTR502_Mega_Target_List.csv and data/raw/catalogs/ASTR502_Master_Photometry_List.csv.
• --quiet prints a compact CSV-like line for the fitted target.

2) Fit a target list (all or subset)

python scripts/fit_target_list.py \
  [--mega-csv PATH] [--phot-csv PATH] \
  [--hostnames HOST1 HOST2 ...] \
  [--output-csv PATH] [--stop-on-error] \
  [--workers N] [--parallel-backend threads|processes] \
  [--emcee] [--nwalkers N] [--nsteps N] [--burn-in N] \
  [--quiet]

Notes:

• Omitting --hostnames runs all hostnames from the mega catalog.
• --workers > 1 enables concurrent fitting.
• --parallel-backend controls concurrency implementation (processes default in script).
• --emcee enables MCMC sampling in addition to the optimization best fit.

3) Isochrone fetch/plot utility classes

python scripts/fetch_iso.py

This file mainly provides reusable classes:

• IsochroneFetcher
• IsochronePlotter

for querying and visualizing ezpadova isochrones from Python if using Parsec models. Note that currently only SPOTs is fully supported.

4) Photometry + distance merge utility class

python scripts/find_mag.py

This file provides PhotometryMerger, which can:

• join photometry and distance catalogs,
• compute absolute magnitudes (G_abs, BP_abs, RP_abs),
• save merged output CSVs (default: data/processed/joined_photometry_and_distances.csv).

Additional runnable service modules

These are under src/astr502/services and can be run directly:

python src/astr502/services/plots.py
python src/astr502/services/gyro.py
python src/astr502/services/regress.py

• plots.py generates observed-vs-table age scatter plots in outputs/figs/.
• gyro.py compares recent fit ages against Kepler & K2 gyrochronology ages.
• regress.py regresses latest interpolated ages against Kepler, K2, or an external comparison CSV and writes a best-fit plot (red=result ages, blue=comparison ages).

Maintainers

Repository owner: James Atkisson
Email: atk@unc.edu

This was written for the ASTR 502 course at the University of North Carolina at Chapel Hill

Instructor: Dr. Andrew Mann