Kepler-89
Star in the constellation Cygnus
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Kepler-89 is a star with four confirmed planets. Kepler-89 is a possible wide binary star.[6]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 49m 19.9343s[2] |
| Declination | +41° 53′ 28.006″[2] |
| Apparent magnitude (V) | 12.4[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F8 IV-V |
| Astrometry | |
| Proper motion (μ) | RA: 2.063(10) mas/yr[2] Dec.: 1.337(11) mas/yr[2] |
| Parallax (π) | 2.1069±0.0086 mas[2] |
| Distance | 1,548 ± 6 ly (475 ± 2 pc) |
| Details[4] | |
| Mass | 1.25+0.03 −0.04 M☉ |
| Radius | 1.61+0.11 −0.12 R☉ |
| Surface gravity (log g) | 4.123±0.055 cgs |
| Temperature | 6,116 K |
| Metallicity [Fe/H] | −0.01±0.04 dex |
| Rotational velocity (v sin i) | 7.33±0.32 km/s |
| Age | 3.9+0.3 −0.2 Gyr |
| Other designations | |
| KOI-94, KIC 6462863, 2MASS J19491993+4153280, Gaia DR2 2076970047474270208[5] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| KIC | data |
Planetary system
The discovery of four planets orbiting the star was announced October 2012 by analyzing data gathered by Kepler space telescope.[4] Follow-up radial velocity measurements confirmed the existence of Kepler-89d, indicating that Kepler-89d is slightly larger and more massive than Saturn.[7] In October 2013, other three planets were confirmed with Kepler-89c and Kepler-89e getting reasonable mass constraints. Transit-timing variations of the outermost planet suggest that additional planets or minor bodies are present in the system.[8]
In 2012, a partial transit of the second outermost planet by the outermost planet was reported. This was the first time a planet-planet transit in front of the star was detected.[9][4] This allowed to determine the mutual inclination of the planets d and e to be 1.15°.[8]
Stephen R. Kane did a dynamical analysis of the Kepler-89 system that demonstrated that planets c and d, although close to the 2:1 secular resonance, are not permanently in a 2:1 resonance configuration.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | <10.5 M🜨 | 0.05 | 3.7 | — | 89.3° | 0.13 RJ |
| c | 7.3-11.8 M🜨 | 0.099 | 10.4 | <0.1 | 88.36° | 0.31 RJ |
| d | 0.33±0.034 MJ | 0.165 | 22.3 | <0.1 | 89.871° | 0.83 RJ |
| e | 11.9-15.5 M🜨 | 0.298 | 54.3 | <0.1 | 89.76° | 0.49 RJ |