Kepler-68

Last updated
Kepler-68
Observation data
Epoch J2000       Equinox J2000
Constellation Cygnus
Right ascension 19h 24m 07.76597s [1]
Declination +49° 02 24.9283 [1]
Apparent magnitude  (V)10.08 [2]
Characteristics
Evolutionary stage Main sequence
Spectral type G1V
Astrometry
Radial velocity (Rv)−20.50±0.23 [1]  km/s
Proper motion (μ)RA: −7.305  mas/yr [1]
Dec.: −10.454  mas/yr [1]
Parallax (π)6.9298 ± 0.0100  mas [1]
Distance 470.7 ± 0.7  ly
(144.3 ± 0.2  pc)
Details [3]
Mass 1.057+0.022
−0.020
  M
Radius 1.2564±0.0084  R
Temperature 5847±75  K
Metallicity [Fe/H]0.11±0.06  dex
Rotational velocity (v sin i)2.4±0.5 [4]  km/s
Age 6.84+0.90
−1.04
  Gyr
Other designations
BD+48 2893, KOI-246, KIC  11295426, TYC  3551-189-1, GSC  03551-00189, 2MASS J19240775+4902249 [4]
Database references
SIMBAD data
KIC data

Kepler-68 is a Sun-like main sequence star located 471 light-years (144 parsecs ) away in the constellation Cygnus. It is known to have at least four planets orbiting around it. [3] The third planet has a mass similar to Jupiter but orbits within the habitable zone. [5]

High resolution imaging observations of Kepler-68 carried out with the lucky imaging instrument AstraLux on the 2.2m telescope at Calar Alto Observatory detected a wide companion candidate approximately 11 arcseconds away. Comparing these observations to the 2MASS positions shows that the companions proper motion is consistent with it being bound to the Kepler-68 system, but further observations are needed to confirm this conclusion. [6] Eleven arcseconds at the distance of Kepler-68 leads to a sky projected separation of approximately 1600 Astronomical units. A circular orbit at that distance would have a period of roughly 50,000 years. [7]

Planetary system

Currently, four planets have been discovered to orbit around Kepler-68. The two innermost planets were discovered by the planetary transit method. Follow-up Doppler measurements helped to determine the mass of Kepler-68b and helped to discover Kepler-68d. [5] [8] There is an additional signal present in the radial velocity measurements indicating another body in the system at a period of greater than 10 years. The mass of this object was initially unknown and it could be either another planet or a stellar companion. [7] In 2023, this fourth planet was confirmed, with a minimum mass about that of Saturn. [3]

The Kepler-68 planetary system [3]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 8.03±0.67  M🜨 0.06135±0.000435.39875259<0.09087.23+0.22
−0.17
°
2.357±0.023  R🜨
c <1.3  M🜨 0.09008±0.000639.605027<0.09987.071+0.087
−0.094
°
0.979±0.019  R🜨
d ≥0.749±0.017  MJ 1.469±0.010632.62±1.030.102±0.016
e≥0.272±0.032  MJ 4.60+0.32
−0.16
3455+348
−169
0.33±0.11

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References

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