Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 20h 33m 54.18821s [2] |
Declination | +35° 15′ 03.02810″ [2] |
Apparent magnitude (V) | 4.61 [3] (4.84 + 7.30) [4] |
Characteristics | |
Spectral type | K6: Ib + B2.5: [3] |
B−V color index | 1.593±0.023 [5] |
Variable type | Lc [6] |
Astrometry | |
Radial velocity (Rv) | −4.6±0.3 [7] km/s |
Proper motion (μ) |
RA: −3.746
[2]
mas/
yr Dec.: −3.408 [2] mas/ yr |
Parallax (π) | 0.7605 ± 0.2285 mas [2] |
Distance | 4072+965 −773 ly (1249+296 −237 pc) [8] |
Absolute magnitude (MV) | −4.1 (−4 + −1.5) [3] |
Orbit [9] | |
Period (P) | 1117±11 d |
Eccentricity (e) | 0.00 (assumed) |
Periastron epoch (T) | 2,447,088±10 JD |
Semi-amplitude (K1) (primary) | 2.0±0.1 km/s |
Details | |
47 Cyg Aa | |
Mass | 12.1±0.2 [10] M☉ |
Radius | 601 [11] R☉ |
Surface gravity (log g) | 1.23 [12] cgs |
Temperature | 4,217 [12] K |
Metallicity [Fe/H] | 0.13 [12] dex |
Age | 17.6±0.6 [10] Myr |
47 Cyg Ab | |
Mass | 0.57 [13] M☉ |
47 Cyg B | |
Mass | 10.96 [13] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
47 Cygni is a triple star [4] [15] system in the northern constellation of Cygnus, and is located around 4,000 light years from the Earth. It is visible to the naked eye with a combined apparent visual magnitude of 4.61. [3] The system is moving closer to the Earth with a heliocentric radial velocity of −4.6 km/s. [7]
The dual nature of this system was recognized by Annie Cannon in 1912, and she assigned the pair separate Henry Draper Catalogue identifiers. [9] They orbit each other with a period of around 143.69 yr. [13] The primary component is itself a spectroscopic binary in a near circular orbit with a period of around 3.06 yr. The a sin i value for the primary is 30.8 ± 1.6 Gm (0.206 ± 0.011 AU), where a is the semimajor axis and i is the orbital inclination. It has been repeatedly resolved by speckle interferometery since 1973. Radio emission was detected from this system in 1985/86. [9]
The supergiant primary is a slow irregular variable with an amplitude of about 0.1 magnitudes. [6] Its angular diameter has been measured at 4.472±0.017 milliarcseconds using interferometry by the Navy Precision Optical Interferometer. [16] At the distance of 1,249 parsecs, [8] it yield a radius of 601 R☉. [11] Its close companion has 57% of the mass of the Sun. [13] The secondary is a hot B-type main-sequence star, but still 2.5 magnitudes fainter than the primary. [4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 20h 33m 54.18821s [2] |
Declination | +35° 15′ 03.02810″ [2] |
Apparent magnitude (V) | 4.61 [3] (4.84 + 7.30) [4] |
Characteristics | |
Spectral type | K6: Ib + B2.5: [3] |
B−V color index | 1.593±0.023 [5] |
Variable type | Lc [6] |
Astrometry | |
Radial velocity (Rv) | −4.6±0.3 [7] km/s |
Proper motion (μ) |
RA: −3.746
[2]
mas/
yr Dec.: −3.408 [2] mas/ yr |
Parallax (π) | 0.7605 ± 0.2285 mas [2] |
Distance | 4072+965 −773 ly (1249+296 −237 pc) [8] |
Absolute magnitude (MV) | −4.1 (−4 + −1.5) [3] |
Orbit [9] | |
Period (P) | 1117±11 d |
Eccentricity (e) | 0.00 (assumed) |
Periastron epoch (T) | 2,447,088±10 JD |
Semi-amplitude (K1) (primary) | 2.0±0.1 km/s |
Details | |
47 Cyg Aa | |
Mass | 12.1±0.2 [10] M☉ |
Radius | 601 [11] R☉ |
Surface gravity (log g) | 1.23 [12] cgs |
Temperature | 4,217 [12] K |
Metallicity [Fe/H] | 0.13 [12] dex |
Age | 17.6±0.6 [10] Myr |
47 Cyg Ab | |
Mass | 0.57 [13] M☉ |
47 Cyg B | |
Mass | 10.96 [13] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
47 Cygni is a triple star [4] [15] system in the northern constellation of Cygnus, and is located around 4,000 light years from the Earth. It is visible to the naked eye with a combined apparent visual magnitude of 4.61. [3] The system is moving closer to the Earth with a heliocentric radial velocity of −4.6 km/s. [7]
The dual nature of this system was recognized by Annie Cannon in 1912, and she assigned the pair separate Henry Draper Catalogue identifiers. [9] They orbit each other with a period of around 143.69 yr. [13] The primary component is itself a spectroscopic binary in a near circular orbit with a period of around 3.06 yr. The a sin i value for the primary is 30.8 ± 1.6 Gm (0.206 ± 0.011 AU), where a is the semimajor axis and i is the orbital inclination. It has been repeatedly resolved by speckle interferometery since 1973. Radio emission was detected from this system in 1985/86. [9]
The supergiant primary is a slow irregular variable with an amplitude of about 0.1 magnitudes. [6] Its angular diameter has been measured at 4.472±0.017 milliarcseconds using interferometry by the Navy Precision Optical Interferometer. [16] At the distance of 1,249 parsecs, [8] it yield a radius of 601 R☉. [11] Its close companion has 57% of the mass of the Sun. [13] The secondary is a hot B-type main-sequence star, but still 2.5 magnitudes fainter than the primary. [4]