Kepler-51
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus | 
| Right ascension | 19h 45m 55.14s | 
| Declination | +49° 56′ 15.65″ | 
| Apparent magnitude (V) | 15.0 | 
| Characteristics | |
| Evolutionary stage | main sequence | 
| Spectral type | G4 | 
| Astrometry | |
| Radial velocity (Rv) | −4.3 km/s | 
| Proper motion (μ) | RA: 0.075±0.020 mas/yr Dec.: −7.451±0.019 mas/yr | 
| Parallax (π) | 1.2457±0.0165 mas | 
| Distance | 2,620 ± 30 ly (800 ± 10 pc) | 
| Details | |
| Mass | 0.96±0.02 M☉ | 
| Radius | 0.87±0.02 R☉ | 
| Luminosity | 0.69 L☉ | 
| Surface gravity (log g) | 4.7±0.1 cgs | 
| Temperature | 5,670±60 K | 
| Metallicity [Fe/H] | +0.05±0.04 dex | 
| Rotational velocity (v sin i) | 5.5±1.0 km/s | 
| Age | 500±250 Myr | 
| Other designations | |
| KOI-620 | |
| Database references | |
| SIMBAD | data | 
Kepler-51 is a Sun-like star that is about 500 million years old. It is orbited by four planets—Kepler-51b, c, d and e—first three of which are super-puffs and have the lowest known densities of any known exoplanet. The transiting planets in the system (b, c and d) are similar in radius to gas giants like Jupiter, but have unusually small masses for their size, only a few times greater than Earth's.