A blue band light curve for a flare of V1581 Cygni. The left-most point shows a 1 sigma error bar. Adapted from Cristaldi and Rodonò (1976) [1] | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
GJ 1245 AC | |
Right ascension | 19h 53m 55.142s [2] |
Declination | +44° 24′ 44.39″ [2] |
Apparent magnitude (V) | 13.46 / 16.75 [3] |
GJ 1245 B | |
Right ascension | 19h 53m 55.141s [4] |
Declination | +44° 24′ 54.15″ [4] |
Apparent magnitude (V) | 14.01 [3] |
Characteristics | |
Spectral type | M6V / M8V [5] / M6V [6] |
Variable type | UV Cet [7] |
Astrometry | |
Radial velocity (Rv) | 3.93±0.38 [4] km/s |
Proper motion (μ) |
RA: 349.363(56)
mas/
yr
[4] Dec.: −480.322(54) mas/ yr [4] |
Parallax (π) | 214.5745 ± 0.0476 mas [4] |
Distance | 15.200 ± 0.003
ly (4.660 ± 0.001 pc) |
Absolute magnitude (MV) | 15.12 / 18.41 [5] / 15.72 [3] |
Orbit [8] | |
Primary | GJ 1245 A |
Companion | GJ 1245 C |
Period (P) | 6147±17 d |
Semi-major axis (a) | 0.8267±0.0008″ |
Eccentricity (e) | 0.334±0.002 |
Inclination (i) | 135.7±0.1° |
Longitude of the node (Ω) | 261.2±0.2° |
Periastron epoch (T) | 51506.8±2.1 |
Argument of periastron (ω) (secondary) | 36.1±0.2° |
Details | |
GJ 1245 A | |
Mass | 0.120±0.001 [5] M☉ |
Radius | 0.146±0.007 [5] R☉ |
Luminosity | 0.0014 [5] L☉ |
Temperature | 2,927 [5] K |
Metallicity [Fe/H] | -0.07 [5] dex |
Age | ~300[ citation needed] Myr |
GJ 1245 C | |
Mass | 0.081±0.001 [5] M☉ |
Radius | 0.087±0.004 [5] R☉ |
Luminosity | 0.0003 [5] L☉ |
Temperature | 2,611 [5] K |
Metallicity [Fe/H] | -0.08 [5] dex |
Other designations | |
GJ 1245 AC: G 208-44, LHS 3494, NLTT 48414, KIC 8451868, 2MASS J19535443+4424541 [9] | |
GJ 1245 B: G 208-45, LHS 3495, NLTT 48415, KIC 8451881, 2MASS J19535508+4424550 [6] | |
Database references | |
SIMBAD | The system |
A | |
C | |
B | |
Location of GJ 1245 in the constellation
Cygnus |
GJ 1245 (Gliese 1245) is a double star with components G 208-44 and G 208-45, located 15.2 light-years (4.7 parsecs) away in the constellation Cygnus. G 208-44 is itself a closer double star made up of two red dwarfs, while G 208-45 is also a red dwarf. GJ 1245 is the 43rd closest stellar system to the Solar System. [10] GJ 1245 A and B are active flare stars, [11] and the pair are collectively designated V1581 Cygni. [12]
The largest of the three stars, GJ 1245 A (G 208-44 A) is only 12% the Sun's mass. [5] Of the other two stars, GJ 1245 C (G 208-44 B), is closest to star A at 2 AU away; [13] it is 8% of the Sun's mass. [5] The third star, GJ 1245 B (G 208-45), is 27 AU away from star A, [13] and is 10% of the Sun's mass; it would appear as bright as Venus does from Earth when viewed from star A.[ citation needed]
A blue band light curve for a flare of V1581 Cygni. The left-most point shows a 1 sigma error bar. Adapted from Cristaldi and Rodonò (1976) [1] | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
GJ 1245 AC | |
Right ascension | 19h 53m 55.142s [2] |
Declination | +44° 24′ 44.39″ [2] |
Apparent magnitude (V) | 13.46 / 16.75 [3] |
GJ 1245 B | |
Right ascension | 19h 53m 55.141s [4] |
Declination | +44° 24′ 54.15″ [4] |
Apparent magnitude (V) | 14.01 [3] |
Characteristics | |
Spectral type | M6V / M8V [5] / M6V [6] |
Variable type | UV Cet [7] |
Astrometry | |
Radial velocity (Rv) | 3.93±0.38 [4] km/s |
Proper motion (μ) |
RA: 349.363(56)
mas/
yr
[4] Dec.: −480.322(54) mas/ yr [4] |
Parallax (π) | 214.5745 ± 0.0476 mas [4] |
Distance | 15.200 ± 0.003
ly (4.660 ± 0.001 pc) |
Absolute magnitude (MV) | 15.12 / 18.41 [5] / 15.72 [3] |
Orbit [8] | |
Primary | GJ 1245 A |
Companion | GJ 1245 C |
Period (P) | 6147±17 d |
Semi-major axis (a) | 0.8267±0.0008″ |
Eccentricity (e) | 0.334±0.002 |
Inclination (i) | 135.7±0.1° |
Longitude of the node (Ω) | 261.2±0.2° |
Periastron epoch (T) | 51506.8±2.1 |
Argument of periastron (ω) (secondary) | 36.1±0.2° |
Details | |
GJ 1245 A | |
Mass | 0.120±0.001 [5] M☉ |
Radius | 0.146±0.007 [5] R☉ |
Luminosity | 0.0014 [5] L☉ |
Temperature | 2,927 [5] K |
Metallicity [Fe/H] | -0.07 [5] dex |
Age | ~300[ citation needed] Myr |
GJ 1245 C | |
Mass | 0.081±0.001 [5] M☉ |
Radius | 0.087±0.004 [5] R☉ |
Luminosity | 0.0003 [5] L☉ |
Temperature | 2,611 [5] K |
Metallicity [Fe/H] | -0.08 [5] dex |
Other designations | |
GJ 1245 AC: G 208-44, LHS 3494, NLTT 48414, KIC 8451868, 2MASS J19535443+4424541 [9] | |
GJ 1245 B: G 208-45, LHS 3495, NLTT 48415, KIC 8451881, 2MASS J19535508+4424550 [6] | |
Database references | |
SIMBAD | The system |
A | |
C | |
B | |
Location of GJ 1245 in the constellation
Cygnus |
GJ 1245 (Gliese 1245) is a double star with components G 208-44 and G 208-45, located 15.2 light-years (4.7 parsecs) away in the constellation Cygnus. G 208-44 is itself a closer double star made up of two red dwarfs, while G 208-45 is also a red dwarf. GJ 1245 is the 43rd closest stellar system to the Solar System. [10] GJ 1245 A and B are active flare stars, [11] and the pair are collectively designated V1581 Cygni. [12]
The largest of the three stars, GJ 1245 A (G 208-44 A) is only 12% the Sun's mass. [5] Of the other two stars, GJ 1245 C (G 208-44 B), is closest to star A at 2 AU away; [13] it is 8% of the Sun's mass. [5] The third star, GJ 1245 B (G 208-45), is 27 AU away from star A, [13] and is 10% of the Sun's mass; it would appear as bright as Venus does from Earth when viewed from star A.[ citation needed]