16 Vulpeculae is a binary star system in the northern constellation Vulpecula.[1] It has a combined apparent visual magnitude of 5.787,[2] which is near the lower limit of visibility to the naked eye. Based upon an annual parallax shift of 14.71±0.50[1] as seen from Earth's orbit, it is located about 222 light years away. The system is moving closer to the Sun with a heliocentric radial velocity of about −37 km/s.[6] It will make its closest approach in about 0.9 million years, coming within 155 light-years (47.42 pc).[10]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Vulpecula |
Right ascension | 20h 02m 01.43152s[1] |
Declination | +24° 56′ 16.9534″[1] |
Apparent magnitude (V) | 5.787[2] 5.93 + 6.22[3] |
Characteristics | |
Spectral type | F2 III[4] |
U−B color index | +0.10[5] |
B−V color index | +0.37[5] |
Astrometry | |
Radial velocity (Rv) | −37.00±3.7[6] km/s |
Proper motion (μ) | RA: 89.31[1] mas/yr Dec.: 69.44[1] mas/yr |
Parallax (π) | 14.71 ± 0.50 mas[1] |
Distance | 222 ± 8 ly (68 ± 2 pc) |
Absolute magnitude (MV) | 2.47[7] |
Orbit[8] | |
Period (P) | 1201 yr |
Semi-major axis (a) | 2.687″ |
Eccentricity (e) | 0.932 |
Inclination (i) | 79.0° |
Longitude of the node (Ω) | 84.5° |
Periastron epoch (T) | B 1863.7 |
Argument of periastron (ω) (secondary) | 276.5° |
Details | |
16 Vul A | |
Mass | 1.34[9] M☉ |
Luminosity | 31.13[10] L☉ |
Surface gravity (log g) | 3.76±0.14[9] cgs |
Temperature | 6,888±234[9] K |
Metallicity [Fe/H] | 0.17[11] dex |
Rotational velocity (v sin i) | 136.1±6.8[7] km/s |
Age | 742[9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
The pair orbit each other with an estimated period of 1,201 years and an orbital eccentricity of 0.932.[8] The magnitude 5.93 primary, component A, displays a stellar classification of F2III,[12] matching an aging F-type giant star. This star is spinning rapidly with a projected rotational velocity of 136 km/s.[7] This is giving the star an oblate shape with an equatorial bulge that is an estimated 21% larger than the polar radius.[13] It is 742[9] million years old with 1.34[9] times the mass of the Sun. The star is radiating 31[10] times the Sun's luminosity from its photosphere at an effective temperature of about 6,888 K.[9]