61 Cygni
 Location of 61 Cygni (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Cygnus |
| 61 Cygni A | |
| Right ascension | 21h 06m 53.9434s |
| Declination | +38° 44′ 57.898″ |
| Apparent magnitude (V) | 5.20 |
| 61 Cygni B | |
| Right ascension | 21h 06m 55.31s |
| Declination | +38° 44′ 31.4″ |
| Apparent magnitude (V) | 6.05 |
| Characteristics | |
| Spectral type | K5V / K7V |
| U−B color index | +1.155 / +1.242 |
| B−V color index | +1.139 / +1.320 |
| Variable type | A: BY Draconis B: Flare star |
| Astrometry | |
| Radial velocity (Rv) | -64.3/-63.5 km/s |
| Proper motion (μ) |
RA: 4156.93/ 4109.17 mas/yr Dec.: 3259.39/ 3144.17 mas/yr |
| Parallax (π) | 285.88 ± 0.54mas |
| Distance | 11.41 ± 0.02 ly (3.498 ± 0.007 pc) |
| Absolute magnitude (MV) | 7.506/8.228 |
| Details | |
| 61 Cygni A | |
| Mass | 0.70 M☉ |
| Radius | 0.665 ±0.005 R☉ |
| Luminosity | 0.153 ±0.01 L☉ |
| Surface gravity (log g) | 4.40 cgs |
| Temperature | 4,526 ±66 K |
| Metallicity [Fe/H] | –0.20 dex |
| Rotation | 35.37 d |
| Age | 6.1 ±1 Gyr |
| 61 Cygni B | |
| Mass | 0.63 M☉ |
| Radius | 0.595 ±0.008 R☉ |
| Luminosity | 0.085 ±0.007 L☉ |
| Surface gravity (log g) | 4.20 cgs |
| Temperature | 4,077 ±59 K |
| Metallicity [Fe/H] | –0.27 dex |
| Rotation | 37.84 d |
| Age | 6.1 ±1 Gyr |
| Orbit | |
| Companion | 61 Cygni B |
| Period (P) | 678 ±34 yr |
| Semi-major axis (a) | 24.272 ±0.592" |
| Eccentricity (e) | 0.49 ±0.03 |
| Inclination (i) | 51 ±2° |
| Longitude of the node (Ω) | 178 ±2° |
| Periastron epoch (T) | 1709 ±16 |
|
Argument of periastron (ω) (secondary) |
149 ±6° |
| Other designations | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
GJ 820 A/B, Struve 2758 A/B, ADS 14636 A/B, V1803 Cyg A/B, GCTP 5077.00 A/B
V* V1803 Cyg, HD 201091, HIP 104214, HR 8085, BD+38°4343, LHS 62, SAO 70919
HD 201092, HIP 104217, HR 8086, BD+38°4344, LHS 63
61 Cygni /ˈsɪɡnɪ/ is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without light pollution.
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