Open science archive // Stellar spectroscopy // Exoplanetary chemistry

Reading the chemistry
of other worlds

A systematic archive documenting the elemental chemistry of exoplanetary systems — measuring what stars are made of, and using that chemistry to understand what their planets are made of too.

Janssen (55 Cnc e) artist’s concept — NASA, ESA, CSA, J. Olmsted (STScI) · JWST 2024

Codex targets in local Galactic space

A Sun-centered view in parsecs. Positions are projected onto the Galactic plane: toward the Galactic center is right; Galactic rotation is up. Coordinates are never moved for appearance.

Loading versioned astrometry…

Search targets

Currently indexed: 12 systems · More added as analysis completes

View all 12 systems →

We combine high-resolution UV, visible, and infrared spectra from HST/STIS and COS, HARPS and HARPS-N, ESPRESSO, UVES, CRIRES+, NIRPS, and other validated archives as appropriate. Reproducible line selection and laboratory-graded atomic data feed multiple abundance engines, comparing 1D/3D and LTE/NLTE treatments where scientifically valid. Measurement, atomic-data, stellar-parameter, and model uncertainties remain traceable to the spectra, line data, models, and methods; results are validated on the Sun and benchmark stars before extension to exoplanet hosts.

“This started as a senior astrophysics thesis in 2010 — three star systems, hand-fitted Gaussians, and a question: can you read the chemistry of a star and know what its planets are made of? I spent fifteen years building lasers and consulting on AI. The question never went away.”
— Ryan Schmitt, founder  ·  Montana, 2026

Get notified when Copernicus publishes

We’re measuring 55 Cancri A now. Get notified when the first Codex entry publishes.