Kepler-16 b
Reference data for Kepler-16 b: Saturn mass and radius, 228.8-day circumbinary orbit around an eclipsing binary in Cygnus, and discovery metrics.
Provenance-Backed Scientific Measurements
Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.
| Parameter | Value | Uncertainty | Method & Epoch | Quality Status | Source Archive |
|---|---|---|---|---|---|
| Distance | 245.4 ly | ± 0.2 ly | Gaia DR3 trigonometric parallax of host star | definitive | ESA Gaia Archive — Data Release 3 |
| Orbital Period | 228.776 d | ± 0.02 d | Multi-epoch transit or astrometric orbital fitting | definitive | NASA Exoplanet Archive |
| Semi-Major Axis | 0.7048 AU | ± 0.0011 AU | Keplerian third-law solution from stellar mass and orbital period | definitive | NASA Exoplanet Archive |
| Planetary Mass | 105.8 M⊕ | ± 5.1 M⊕ | Equivalent to 0.333 ± 0.016 Jupiter masses, constrained via binary eclipse timing and radial velocities. | definitive | NASA Exoplanet Archive |
| Planetary Radius | 8.45 R⊕ | ± 0.03 R⊕ | Equivalent to 0.754 ± 0.003 Jupiter radii. | definitive | NASA Exoplanet Archive |
| Equilibrium Temperature | 185 K | ± 8 K | Radiative equilibrium calculation from bolometric stellar insolation | high-confidence | NASA Exoplanet Archive |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Kepler-16 b — Circumbinary Saturn-Mass Planet at RA 19h 16m 18.17s, Dec +51° 45′ 26.8″ within Cygnus, alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.
Astrophysical Context & Structure
Confirmed in September 2011 by Laurence Doyle and collaborators, Kepler-16 b provided the first rock-solid demonstration of a circumbinary planet transiting both members of an eclipsing stellar pair. The central binary consists of a 0.69-solar-mass K-type main-sequence star and a 0.20-solar-mass M-type red dwarf locked in an eccentric 41.08-day mutual orbit separated by 0.22 astronomical units. Outside this stellar dance, the planet sweeps around the system's common barycenter every 228.78 days at 0.705 astronomical units.
Because the planet's gravity slightly perturbs the eclipse timings of the central stars while transiting both disks, astronomers pinned down the masses and radii of all three bodies to fractional-percent precision. Weighing 105.8 Earth masses (0.333 Jupiter masses) and spanning 8.45 Earth radii (0.754 Jupiter radii), Kepler-16 b has a mean density of 0.96 grams per cubic centimeter—making it a cold, gas-ice giant slightly denser than Saturn.
Unlike planets orbiting single stars, a circumbinary world's transit intervals and durations vary dramatically from cycle to cycle because the target stars are constantly moving along their own orbit. Moreover, gravitational torque from the binary causes the planet's orbital plane to precess slowly, temporarily halting transits across the primary star for multi-decade intervals. In 2022, astronomers achieved the first ground-based radial velocity confirmation of Kepler-16 b using the SOPHIE spectrograph.
Practical Visual Observing Guide
- The eclipsing binary host Kepler-16 shines at V ~ 12.00 in northern Cygnus, within reach of 6-inch amateur telescopes.
- Primary stellar eclipses drop the system's brightness by ~13% every 41.08 days.
- Planetary transits across the primary star produce a ~1.7% dip when the precessing orbital plane aligns with Earth.
Catalog Cross-Identifications & Aliases
Common Aliases: Kepler-16 (AB) b · Kepler-16b · KOI-1611.02 · KIC 12644769 b
| Catalog Authority | Identifier |
|---|---|
| NASAEXOPLANET | Kepler-16 b |
| SIMBAD | Kepler-16 b |
Related Objects, Comparisons & Guides
Kepler-452 b — Super-Earth Around a G2 Star
Reference profile for Kepler-452 b: 384.8-day orbit, 1.05 AU separation from a G2V star, 1.63 Earth radii, and validation status.
Kepler-186 f — First Earth-Size Habitable World
Reference data for Kepler-186 f: 1.17 Earth radii, 129.9-day habitable-zone orbit around an M1 dwarf in Cygnus, and insolation metrics.
51 Pegasi b (Dimidium First Hot Jupiter)
Coordinates, Gaia DR3 distance (15.46 pc), 4.2308-day orbital period, Nobel-winning radial-velocity discovery, and observing guide for 51 Pegasi b.
Exoplanet Transit & Radial Velocity Methods
How astronomers detect and characterize exoplanets using photometric transit depth ((Rp/R*)²), Doppler radial velocity (M sin i), and JWST transmission spectra.
Celestial Coordinates (RA & Dec) Explained
Practical reference to J2000 equatorial coordinates: Right Ascension (RA in hours, minutes, seconds), Declination (Dec in degrees), and sexagesimal conversion.
Scientific Sources & Dataset Provenance
- NASA Exoplanet Archive (2026-10-01 snapshot): Akeson, R. L., et al. 2013, PASP, 125, 989; NASA Exoplanet Archive (IPAC/Caltech) — NASA Exoplanet Science Institute (NExScI / Caltech / IPAC)
- ESA Gaia Archive — Data Release 3 (DR3 (2022-06-13)): Gaia Collaboration, Vallenari, A., et al. 2023, A&A, 674, A1 (Gaia Data Release 3) — European Space Agency / Gaia DPAC