Research Database

Complete Census of Co-moving Pairs Of Stars

C3PO is a high-resolution spectroscopic survey of 125 bright co-moving stellar pairs. The database brings together precise stellar parameters, chemistry differences, astrometry, measured velocities, equivalent widths, and interactive spectra for wide-binary science.

125 co-moving stellar pairs in the curated C3PO catalog
250 bright F/G/K stars with high-SNR spectroscopic analysis
6 papers in the C3PO series, linked to public arXiv and media artifacts
23 chemical elements compared star-by-star
Data Products

A database built for pair-by-pair comparison

The public site stays browser-ready, while the full database remains self-contained in the separate C3PO_Database directory with source tables, analysis-ready pickle files, notebooks, scripts, and full CSV spectra.

C3PO database workbench visual

Catalog

Filter wide binaries by co-natal status, planet ingestion candidates, separation, Δ[Fe/H], and available spectra.

Browse catalog
High-resolution spectra visual

Spectra

Inspect high-point browser previews for available C3PO stars, with links back to the source CSV filenames in the database package.

View spectra
C3PO binary flight visual

Flight

Fly through a self-contained C3PO binary scene using Gaia sky directions, measured stellar colors, catalog pair spacing, and survey flags.

Enter flight applet
Live Workbench

Work with the C3PO data directly

Each embedded panel is the same self-contained tool as its full page. On narrow mobile screens, the heavier flight and spectra panels become lightweight launch cards so the landing page stays fast.

C3PO pair flight

Navigate the Gaia star field with Space and arrow-key controls, then jump to curated C3PO wide binaries rendered as two measured stars inside one pair-level ring.

Open full screen

Open the full flight applet

The landing page skips the embedded 3D Gaia field on phones to keep the first load light. The full flight page is still available when you want the interactive view.

Pair catalog

Search, filter, sort, and page through the curated 125-pair browser catalog while preserving links into the spectra viewer for stars with available observations.

Open catalog

Spectra viewer

Inspect high-point spectra previews linked back to the full-resolution C3PO database files, with instrument filtering, interactive selection, zooming, and panning.

Open viewer

Open the full spectra viewer

The landing page skips the embedded spectra tool on phones to save data. The full viewer remains one tap away for detailed line inspection.

Publications

The C3PO series

Six C3PO papers use co-moving pairs as controlled laboratories for chemistry, planet signatures, stellar evolution, magnetic activity, rotation, and wide-binary gravity.

C3PO I

Stellar twins stay chemically alike across enormous separations

Yong et al. 2023, MNRAS 526, 2181

C3PO I shows that many co-moving pairs remain chemically twin-like out to roughly a million Earth-Sun distances, defining the survey's cleanest birth-signature regime.

Co-natal boundary illustration
C3PO II

At least one in a dozen Sun-like stars may have swallowed planets

Liu et al. 2024, Nature 627, 501

Using co-natal pairs as controlled experiments, C3PO II identifies seven new planet-ingestion candidates, an occurrence rate of about eight percent.

Planet ingestion illustration
C3PO III

Lithium only speaks clearly among true stellar twins

Sun et al. 2025, ApJ 978, 107

C3PO III shows that planet-engulfment lithium signatures are discernible only for highly similar stars; ordinary stellar evolution can otherwise mask the signal.

Lithium signal and stellar noise
C3PO IV

Planet-building chemistry tracks stellar magnetic activity

Yu et al. 2025, MNRAS 538, 2408

C3PO IV finds that co-natal stars depleted in refractory elements are more magnetically active, connecting planet-formation chemistry to stellar behavior.

Magnetic activity illustration
C3PO V

Stellar spin-down explains the lithium dip

Sun et al. 2025, ApJ 991, 185

C3PO V uses co-moving pairs around the hot side of the Li dip to isolate rotation-driven mixing as the dominant lithium-depletion process.

Rotation and lithium dip illustration
C3PO VI

Meter-per-second line-of-sight speeds turn wide binaries into gravity tests

Saad & Ting 2025, arXiv:2512.19652

C3PO VI measures meter-per-second line-of-sight speed differences for 100 wide binaries, improving on Gaia radial velocities and testing MOND-scale dynamics.

Wide-binary velocity gravity test illustration