Kepler-68 is a Sun-like main sequence star. It is known to have at least three planets orbiting around it. The outermost planet has a mass similar to Jupiter but orbits within the habitable zone.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 24m 07.7660s[1] |
| Declination | +49° 02′ 24.9282″[1] |
| Apparent magnitude (V) | 10.08[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G1V C |
| Astrometry | |
| Proper motion (μ) | RA: −7.334 ± 0.039[1] mas/yr Dec.: −10.430 ± 0.048[1] mas/yr |
| Parallax (π) | 6.9076 ± 0.0208 mas[1] |
| Distance | 472 ± 1 ly (144.8 ± 0.4 pc) |
| Details[3] | |
| Mass | 1.079±0.051 M☉ |
| Radius | 1.243±0.019 R☉ |
| Temperature | 5793±74 K |
| Metallicity [Fe/H] | 0.12 (± 0.074) dex |
| Rotational velocity (v sin i) | 2.4±0.5[4] km/s |
| Age | 6.31+0.84 −0.79 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| KIC | data |
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]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 7.65+1.37 −1.32 M🜨 |
0.06170±0.00056 | 5.398763 | — | 87.60±0.90° | 2.31+0.06 −0.09 R🜨 |
| c | 2.02+1.72 −1.78 M🜨 |
0.09059±0.00082 | 9.605065 | — | 86.93±0.41° | 0.953+0.037 −0.042 R🜨 |
| d | ≥0.77±0.03 MJ | 1.40±0.03 | 634.6+4.1 −3.7 |
0.112+0.035 −0.034 |
— | — |
| e (unconfirmed) | — | ~5? | >3650 | — | — | — |
Currently, three planets have been discovered to orbit around Kepler-68. Two of the 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.[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 is unknown and it could be either another planet or a stellar companion.[7]
Kepler-68 system | |
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Constellation of Cygnus | |||||||||||
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