Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cygnus |
31 Cygni A | |
Right ascension | 20h 13m 37.908s [1] |
Declination | +46° 44′ 28.76″ [1] |
Apparent magnitude (V) | 3.73 - 3.89 [2] |
HD 192379 | |
Right ascension | 20h 13m 39.199s [3] |
Declination | +46° 42′ 42.70″ [3] |
Apparent magnitude (V) | 6.99 [4] |
Characteristics | |
31 Cygni A | |
Spectral type | K3Ib + B2IV-V [5] |
Variable type | Algol [2] |
HD 192579 | |
Evolutionary stage | main sequence [4] [3] |
Spectral type | B5V [4] |
Astrometry | |
31 Cygni A | |
Radial velocity (Rv) | −7.41±0.08 [6] km/s |
Proper motion (μ) |
RA: 1.744
[1]
mas/
yr Dec.: 3.390 [1] mas/ yr |
Parallax (π) | 2.9167 ± 0.1327 mas [1] |
Distance | 1,120 ± 50
ly (340 ± 20 pc) |
HD 192579 | |
Proper motion (μ) |
RA: 3.906
[3]
mas/
yr Dec.: 1.978 [3] mas/ yr |
Parallax (π) | 2.9160 ± 0.0336 mas [3] |
Distance | 1,120 ± 10
ly (343 ± 4 pc) |
Orbit [7] | |
Primary | 31 Cygni Aa |
Companion | 31 Cygni Ab |
Period (P) | 3,784.3 d |
Eccentricity (e) | 0.2084±0.0031 |
Periastron epoch (T) | 2,452,345±9 |
Argument of periastron (ω) (secondary) | 204.5±1.0° |
Semi-amplitude (K1) (primary) | 13.94±0.04 km/s |
Semi-amplitude (K2) (secondary) | 18.0 [8] km/s |
Details | |
K supergiant | |
Mass | 6.73 [8] M☉ |
Radius | 127 [9] R☉ |
Luminosity | 2,512 - 2,559 [9] L☉ |
Temperature | 4,043±170 [9] K |
B dwarf | |
Mass | 5.22 [8] M☉ |
Radius | 5.2±0.5 [10] R☉ |
Temperature | 16,500+1,000 −2,000 [11] K |
Age | 39.8 [12] Myr |
HD 192579 | |
Mass | 4.1 [3] M☉ |
Radius | 3.3 [3] R☉ |
Luminosity | 373 [3] L☉ |
Surface gravity (log g) | 4.04 [3] cgs |
Temperature | 13,949 [3] K |
Metallicity [Fe/H] | +0.68 [3] dex |
Other designations | |
31 Cygni A (HD 192577): V695 Cyg, HD 192577, BD+46°2882, HIP 99675, HR 7735, SAO 49337 | |
HD 192579: HD 192579, BD+46°2883, HIP 99676, SAO 49338 | |
Database references | |
SIMBAD | data |
HD 192579 |
31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, ο2 Cygni or V695 Cygni, is a ternary star system about 750 light years away in the constellation Cygnus.
The Bayer designation ο ( omicron) has been variously applied to two or three of the stars 30, 31, and 32 Cygni. 31 Cygni has been designated, variously, as ο1 or ο2 Cygni — therefore for clarity, it is preferred to use the Flamsteed designation 31 Cygni. [13]
31 Cygni consists of a visible pair of stars 109 ″ apart as of 2016, and the brighter of the two is also a spectroscopic binary. 31 Cygni A is also designated HD 192577 and HR 7735, while its 7th-magnitude visual companion is designated HD 192579. Some multiple star catalogues designate a 13th-magnitude star 36″ from 31 Cygni A as 31 Cygni B, and HD 192579 as 31 Cygni C. [14] The 13th-magnitude star is likely to be an unrelated background object. [15]
The spectroscopic pair are an orange supergiant of spectral type K3Ib and a blue-white star likely to be evolving off the main sequence with a spectral type of B2IV-V. The visible companion is a 7th-magnitude B5 main sequence star. [4] [3]
31 Cygni A is an Algol-type eclipsing binary and ranges between magnitudes 3.73 and 3.89 over a period of ten years. [7] The eclipsing system has been studied in attempts to determine an accurate direct mass for a red supergiant. The value 6.73 M☉ is believed to be accurate to about 2%, but there are some discrepancies in the orbital fit. [8]
30 Cygni is another naked eye star a tenth of a degree away, forming a bright triple.
32 Cygni is about a degree away to the north, also a detached eclipsing binary system. It comprises a large cool evolved star and a small hot main sequence or subgiant companion.
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cygnus |
31 Cygni A | |
Right ascension | 20h 13m 37.908s [1] |
Declination | +46° 44′ 28.76″ [1] |
Apparent magnitude (V) | 3.73 - 3.89 [2] |
HD 192379 | |
Right ascension | 20h 13m 39.199s [3] |
Declination | +46° 42′ 42.70″ [3] |
Apparent magnitude (V) | 6.99 [4] |
Characteristics | |
31 Cygni A | |
Spectral type | K3Ib + B2IV-V [5] |
Variable type | Algol [2] |
HD 192579 | |
Evolutionary stage | main sequence [4] [3] |
Spectral type | B5V [4] |
Astrometry | |
31 Cygni A | |
Radial velocity (Rv) | −7.41±0.08 [6] km/s |
Proper motion (μ) |
RA: 1.744
[1]
mas/
yr Dec.: 3.390 [1] mas/ yr |
Parallax (π) | 2.9167 ± 0.1327 mas [1] |
Distance | 1,120 ± 50
ly (340 ± 20 pc) |
HD 192579 | |
Proper motion (μ) |
RA: 3.906
[3]
mas/
yr Dec.: 1.978 [3] mas/ yr |
Parallax (π) | 2.9160 ± 0.0336 mas [3] |
Distance | 1,120 ± 10
ly (343 ± 4 pc) |
Orbit [7] | |
Primary | 31 Cygni Aa |
Companion | 31 Cygni Ab |
Period (P) | 3,784.3 d |
Eccentricity (e) | 0.2084±0.0031 |
Periastron epoch (T) | 2,452,345±9 |
Argument of periastron (ω) (secondary) | 204.5±1.0° |
Semi-amplitude (K1) (primary) | 13.94±0.04 km/s |
Semi-amplitude (K2) (secondary) | 18.0 [8] km/s |
Details | |
K supergiant | |
Mass | 6.73 [8] M☉ |
Radius | 127 [9] R☉ |
Luminosity | 2,512 - 2,559 [9] L☉ |
Temperature | 4,043±170 [9] K |
B dwarf | |
Mass | 5.22 [8] M☉ |
Radius | 5.2±0.5 [10] R☉ |
Temperature | 16,500+1,000 −2,000 [11] K |
Age | 39.8 [12] Myr |
HD 192579 | |
Mass | 4.1 [3] M☉ |
Radius | 3.3 [3] R☉ |
Luminosity | 373 [3] L☉ |
Surface gravity (log g) | 4.04 [3] cgs |
Temperature | 13,949 [3] K |
Metallicity [Fe/H] | +0.68 [3] dex |
Other designations | |
31 Cygni A (HD 192577): V695 Cyg, HD 192577, BD+46°2882, HIP 99675, HR 7735, SAO 49337 | |
HD 192579: HD 192579, BD+46°2883, HIP 99676, SAO 49338 | |
Database references | |
SIMBAD | data |
HD 192579 |
31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, ο2 Cygni or V695 Cygni, is a ternary star system about 750 light years away in the constellation Cygnus.
The Bayer designation ο ( omicron) has been variously applied to two or three of the stars 30, 31, and 32 Cygni. 31 Cygni has been designated, variously, as ο1 or ο2 Cygni — therefore for clarity, it is preferred to use the Flamsteed designation 31 Cygni. [13]
31 Cygni consists of a visible pair of stars 109 ″ apart as of 2016, and the brighter of the two is also a spectroscopic binary. 31 Cygni A is also designated HD 192577 and HR 7735, while its 7th-magnitude visual companion is designated HD 192579. Some multiple star catalogues designate a 13th-magnitude star 36″ from 31 Cygni A as 31 Cygni B, and HD 192579 as 31 Cygni C. [14] The 13th-magnitude star is likely to be an unrelated background object. [15]
The spectroscopic pair are an orange supergiant of spectral type K3Ib and a blue-white star likely to be evolving off the main sequence with a spectral type of B2IV-V. The visible companion is a 7th-magnitude B5 main sequence star. [4] [3]
31 Cygni A is an Algol-type eclipsing binary and ranges between magnitudes 3.73 and 3.89 over a period of ten years. [7] The eclipsing system has been studied in attempts to determine an accurate direct mass for a red supergiant. The value 6.73 M☉ is believed to be accurate to about 2%, but there are some discrepancies in the orbital fit. [8]
30 Cygni is another naked eye star a tenth of a degree away, forming a bright triple.
32 Cygni is about a degree away to the north, also a detached eclipsing binary system. It comprises a large cool evolved star and a small hot main sequence or subgiant companion.