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Kepler-16 A/B
An artist's rendering of the Kepler-16 system, showing the binary star being orbited by Kepler-16b.
Credit: NASA/JPL-Caltech
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 16m 18.175s[1]
Declination +51° 45′ 26.76″[1]
Spectral type K / M[2]
Distance 196 ly
(60 pc)
Primary Kepler-16A
Companion Kepler-16B
Period (P) 41.079220 (± 0.000078) d
Semi-major axis (a) 0.22431 (± 0.00035) AU
Eccentricity (e) 0.15944 (± 0.00062)
Inclination (i) 90.30401 (± 0.0019)°
Longitude of the node (Ω)
Periastron epoch (T) BJD 2455212.12316
Argument of periastron (ω)
263.464 (± 0.027)°
Mass 0.6897 (± 0.0035) M
Radius 0.6489 (± 0.0013) R
Luminosity 0.148[4] L
Surface gravity (log g) 4.6527 (± 0.0017) cgs
Temperature 4450 (± 150) K
Metallicity [Fe/H] -0.3 (± 0.2) dex
Rotation 35.1 ± 1.0 days[5]
Mass 0.20255 (± 0.00065) M
Radius 0.22623 (± 0.00059) R
Luminosity ~0.0057[4] L
Surface gravity (log g) 5.0358 (± 0.0017) cgs
Temperature ~3311[4] K
Other designations
KIC 12644769[2][3], 2MASS 19161817+5145267[2]
Database references
KIC data

Kepler-16 is a binary star system in the constellation of Cygnus[6] that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a K-type main-sequence star and the secondary, Kepler-16B, is an M-type red dwarf. They are separated by 0.22 AU, and complete an orbit around a common center of mass every 41 days.

The system is host to one known extrasolar planet in circumbinary orbit: the Saturn-sized Kepler-16b.

Planetary system[edit]

Main article: Kepler-16b

Kepler-16b is a gas giant that orbits the two stars in the Kepler-16 system.[3] The planet is a third of Jupiter's mass and slightly smaller than Saturn at 0.7538 Jupiter radii, but is more dense. Kepler-16b completes a nearly circular orbit every 228.776 days.

The Kepler-16 planetary system[7]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.333 MJ 0.7048 228.776 0.0069 90.032° 0.7538 RJ


  1. ^ a b Zacharias, N. (2009). "Third U.S. Naval Observatory CCD Astrograph Catalog (UCAC3)". VizieR On-line Data Catalog. Bibcode:2009yCat.1315....0Z. 
  2. ^ a b c Jean Schneider (2011). "Notes for star Kepler-16 (AB)". Extrasolar Planets Encyclopaedia. Retrieved 23 September 2011. 
  3. ^ a b c Doyle, Laurance R.; Carter, Joshua A.; Fabrycky, Daniel C.; Slawson, Robert W.; Howell, Steve B.; Winn, Joshua N.; Orosz, Jerome A.; Prša, Andrej; Welsh, William F.; et al. (2011). "Kepler-16: A Transiting Circumbinary Planet". Science. 333 (6049): 1602–6. arXiv:1109.3432Freely accessible. Bibcode:2011Sci...333.1602D. doi:10.1126/science.1210923. PMID 21921192. 
  4. ^ a b c Haghighipour, Nader; Kaltenegger, Lisa (24 October 2013). "Calculating the Habitable Zone of Binary Star Systems. II. P-type Binaries". The Astrophysical Journal. 777 (2): 13. arXiv:1306.2890Freely accessible. Bibcode:2013ApJ...777..166H. doi:10.1088/0004-637X/777/2/166. 
  5. ^ Winn, Joshua N.; et al. (2011). "Spin-Orbit Alignment for the Circumbinary Planet Host Kepler-16 A". The Astrophysical Journal Letters. 741 (1). L1. arXiv:1109.3198Freely accessible. Bibcode:2011ApJ...741L...1W. doi:10.1088/2041-8205/741/1/L1. 
  6. ^ Drake, Nadia. "On Kepler-16b, shadows come in pairs". Science News. Society for Science & the Public. Retrieved 16 September 2011. 
  7. ^ Jean Schneider (2011). "Notes for Planet Kepler-16 (AB) b". Extrasolar Planets Encyclopaedia. Retrieved 23 September 2011. 

Coordinates: Sky map 19h 16m 18.17s, +51° 45′ 26.78″