17 Cygni is the Flamsteed designation for a multiple star system[5] in the northern constellation of Cygnus. It has an apparent visual magnitude of 5.00,[2] so, according to the Bortle scale, it is visible from suburban skies at night. Measurements of the annual parallax find a shift of 0.0477â³,[1] which is equivalent to a distance of around 68.5 ly (21.0 pc) from the Sun. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.451â³/year.[14]
Quick facts Observation data Epoch J2000 Equinox J2000, Apparent magnitude (V) ...
17 Cygni
Location of 17 Cygni (circled in red) |
Observation data
Epoch J2000 Equinox J2000 |
| Constellation |
Cygnus |
| A |
| Right ascension |
19h 46m 25.600s[1] |
| Declination |
+33° 43â² 39.35â³[1] |
| Apparent magnitude (V) |
5.00[2] |
| B |
| Right ascension |
19h 46m 27.547s[3] |
| Declination |
+33° 43â² 48.89â³[3] |
| Apparent magnitude (V) |
8.55[4] |
| Characteristics |
| Spectral type |
F7 V[2] + K6 V + K3 V + K3 V[5] |
| BâV color index |
0.46[2] |
| Astrometry |
|---|
| A |
|---|
| Radial velocity (Rv) | +4.1[6] km/s |
| Proper motion (μ) | RA: +22.745 mas/yr[1]
Dec.: â448.311 mas/yr[1] |
| Parallax (Ï) | 47.6516±0.0675 mas[1] |
| Distance | 68.45 ± 0.10 ly
(20.99 ± 0.03 pc) |
| Absolute magnitude (MV) | +3.34[7] |
| B |
|---|
| Radial velocity (Rv) | +3.7[6] km/s |
| Proper motion (μ) | RA: +21.547 mas/yr[3]
Dec.: â438.730 mas/yr[3] |
| Parallax (Ï) | 47.7379±0.0185 mas[3] |
| Distance | 68.32 ± 0.03 ly
(20.948 ± 0.008 pc) |
| Absolute magnitude (MV) | +6.91[7] |
| Details |
|---|
| A |
|---|
| Mass | 1.24[8] Mâ |
| Radius | 1.538[9] Râ |
| Luminosity | 3.66[10] Lâ |
| Surface gravity (log g) | 4.262[10] cgs |
| Temperature | 6,455[10] K |
| Metallicity [Fe/H] | 0.027[10] dex |
| Rotational velocity (v sin i) | 9[2] km/s |
| Age | 2.8[7] Gyr |
| B |
|---|
| Mass | 0.78[11] Mâ |
| Radius | 0.70[11] Râ |
| Luminosity | 0.21[11] Lâ |
| Surface gravity (log g) | 4.62[11] cgs |
| Temperature | 4,652[11] K |
| F |
|---|
| Mass | 0.77[11] Mâ |
| Radius | 0.71[11] Râ |
| Luminosity | 0.24[11] Lâ |
| Surface gravity (log g) | 4.62[11] cgs |
| Temperature | 4,789[11] K |
| Rotational velocity (v sin i) | 3.6[12] km/s |
| G |
|---|
| Mass | 0.75[11] Mâ |
| Radius | 0.71[11] Râ |
| Luminosity | 0.22[11] Lâ |
| Surface gravity (log g) | 4.61[11] cgs |
| Temperature | 4,686[11] K |
| Rotational velocity (v sin i) | 3.0[12] km/s |
| Other designations |
|---|
| 17 Cyg, BD+33°3587, GJ 767.1, GJ 9670, HD 187013, HIP 97295, HR 7534, SAO 68827[13] |
| Database references |
|---|
| SIMBAD | data |
| B |
| F |
| G |
Close
This system consists of two visual binary systems that were discovered by John Herschel in the 1820s. Components A and B form a bright, wide pair with an angular separation of 26.0 arcsecond and an estimated orbital period of ~6,200 years. The faint, close system consists of components F and G with a separation of 2.6 arcsecond and a period of 238 years. The two binaries form a hierarchical system with a separation of about 800 arcseconds and orbital period of 3.7 million years or more.[5] Although the CCDM lists four other companions, these are not associated with the system.[15]
The stellar classification of the primary star, component A, is F7 V,[2] which means it is a main sequence star like the Sun. The star has 1.24[8] times the mass of the Sun and 1.54[9] times the Sun's radius. It is some 2.8[7] billion years old and shines with 3.66[10] times the Sun's luminosity. The effective temperature of the stellar atmosphere is 6,455[10] K, giving it the yellow-white hued glow of an F-type star.[16]
