Overview
The Kepler Input Catalog (KIC) is an astronomical database compiled to support the NASA Kepler space telescope mission, which was launched in 2009 to search for transiting exoplanets. The catalog provides photometric measurements and derived stellar parameters for stars located within the Kepler field of view, a 105‑square‑degree region centered on the constellations Cygnus and Lyra.
Purpose and Development
The KIC was created to enable the selection of optimal target stars for Kepler’s high‑precision photometric monitoring. Ground‑based observations, primarily in the Sloan g, r, i, z filters supplemented by the intermediate‑band D51 filter and near‑infrared data from the Two Micron All Sky Survey (2MASS), were processed to produce a homogeneous set of stellar attributes. The catalog was compiled by a collaboration led by the Kepler Asteroseismic Science Consortium and made publicly available through the Mikulski Archive for Space Telescopes (MAST).
Content and Structure
| Parameter (typical columns) | Description |
|---|---|
| KIC ID | Unique integer identifier assigned to each entry. |
| RA, Dec (J2000) | Celestial coordinates. |
| Kepler magnitude (Kp) | Broad‑band magnitude calibrated for the Kepler photometer. |
| g, r, i, z, D51 | Ground‑based photometric magnitudes. |
| J, H, K_s | Near‑infrared magnitudes from 2MASS. |
| T_eff | Effective temperature (K), derived from photometry. |
| log g | Surface gravity (cgs). |
| [Fe/H] | Metallicity estimate. |
| Radius, Mass | Approximate stellar radius and mass (when available). |
| Extinction (A_V) | Estimated interstellar extinction. |
The original release listed approximately 13 million objects down to a limiting Kepler magnitude of Kp ≈ 16. The catalog thus includes the primary sample of ~150 000 stars that were observed intensively during Kepler’s primary mission, as well as numerous fainter background objects.
Use in the Kepler Mission
- Target Selection – The KIC informed the prioritization of stars with suitable temperatures, luminosities, and variability characteristics for detecting Earth‑size planets in the habitable zone.
- Data Interpretation – Stellar parameters from the KIC were employed to convert observed transit depths into planetary radii and to assess habitability metrics.
- Asteroseismology – The catalog supported the identification of stars suitable for asteroseismic analysis, enabling precise determinations of stellar ages and structures.
Updates and Complementary Catalogs
Subsequent refinements to stellar properties have been released under the name Kepler Stellar Properties Catalog (KSPC), incorporating spectroscopic follow‑up, Gaia astrometry, and revised photometric calibrations. These updates supersede many of the original KIC parameters for research requiring higher precision, but the KIC identifiers remain the primary cross‑reference for Kepler data products.
Access
The full KIC dataset, along with documentation, is hosted at the Mikulski Archive for Space Telescopes (MAST) and can be queried via web interfaces, TAP services, and bulk download options.
See Also
- Kepler Space Telescope
- Kepler Objects of Interest (KOI)
- Gaia Data Release catalogs
- Two Micron All Sky Survey (2MASS)
References
- Brown, T. M., et al. (2011). Kepler Input Catalog: Photometric Calibration of Stars for the Kepler Mission. Astronomical Journal, 142, 112.
- Huber, D., et al. (2014). Fundamental Properties of Kepler Stars: A Revised Stellar Properties Catalog. The Astrophysical Journal Supplement Series, 211, 2.
- The Mikulski Archive for Space Telescopes (MAST), Kepler Input Catalog. https://archive.stsci.edu/kepler/kic.html
Note: All information presented is drawn from publicly available mission documentation and peer‑reviewed literature.