# Data Dictionary - Exoplanet Catalog (NASA Exoplanet Archive) - every confirmed planet + host star, cleaned

**Units:** stated per column in the descriptions below (this is a relational table; columns mix units).

| column | type | description |
|---|---|---|
| `planet` | str | Planet name (primary key) |
| `host_star` | str | Host star name |
| `n_stars` | int | Number of stars in the system |
| `n_planets` | int | Number of known planets in the system |
| `discovery_method` | str | Detection method (Transit, Radial Velocity, …) |
| `discovery_year` | int | Year of discovery |
| `discovery_facility` | str | Discovering facility / survey |
| `orbital_period_days` | float | Orbital period (days) |
| `semi_major_axis_au` | float | Semi-major axis (AU) |
| `eccentricity` | float | Orbital eccentricity |
| `radius_earth` | float | Planet radius (Earth radii) |
| `mass_earth` | float | Planet mass / best-mass (Earth masses) |
| `equilibrium_temp_k` | float | Equilibrium temperature (K) |
| `star_spectral_type` | str | Host-star spectral type |
| `star_temp_k` | float | Host-star effective temperature (K) |
| `star_radius_sun` | float | Host-star radius (solar radii) |
| `star_mass_sun` | float | Host-star mass (solar masses) |
| `distance_pc` | float | Distance to the system (parsecs) |
| `ra_deg` | float | Right ascension (degrees) |
| `dec_deg` | float | Declination (degrees) |

*Source: NASA Exoplanet Archive (Caltech/IPAC under contract with NASA).*