Kappa Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 36m 53.449s |
| Declination | −07° 01′ 38.92″ |
| Apparent magnitude (V) | +4.957 |
| Characteristics | |
| Spectral type | B0.5 III |
| U−B color index | −0.861 |
| B−V color index | −0.028 |
| Astrometry | |
| Radial velocity (Rv) | −19.4±4.2 km/s |
| Proper motion (μ) | RA: +0.974 mas/yr Dec.: −3.241 mas/yr |
| Parallax (π) | 1.9758±0.1533 mas |
| Distance | 1,700 ± 100 ly (510 ± 40 pc) |
| Absolute magnitude (MV) | −3.60 |
| Details | |
| Mass | 15.50±0.61 M☉ |
| Radius | 12.5 R☉ |
| Luminosity | 52,630 L☉ |
| Surface gravity (log g) | 3.5 cgs |
| Temperature | 26,500 K |
| Metallicity [Fe/H] | −0.16 dex |
| Rotational velocity (v sin i) | 265 km/s |
| Age | 11.1±0.5 Myr |
| Other designations | |
| κ Aquilae, Kappa Aql, κ Aql, 39 Aquilae, BD−07 5006, FK5 737, GC 27107, HD 184915, HIP 96483, HR 7446, SAO 143600, PPM 203088 | |
| Database references | |
| SIMBAD | data |
Kappa Aquilae is a star in the equatorial constellation of Aquila. Its name is a Bayer designation that is Latinized from κ Aquilae, and abbreviated Kappa Aql or κ Aql. This is a faint star with an apparent visual magnitude of +4.957, which is bright enough to be seen with the naked eye in dark suburban skies. The annual parallax is only 1.98 mas, which equates to a distance of approximately 1,700 light-years (520 parsecs) from Earth (with a 6% margin of error).
The spectrum of Kappa Aquilae matches a stellar classification of B0.5 III, where the luminosity class of III is typically associated with evolved giant stars. It is spinning rapidly with a projected rotational velocity of 265 km/s and in the past has been classified as a Be star, despite the lack of an 'e' in the class. However, the weak emission is most likely coming from the outflow of a hot stellar wind rather than a decretion disk. This is a star with 15.50 times the Sun's mass and 12.5 times the radius of the Sun. Massive stars like this are luminous; it is radiating 52,630 times the Sun's luminosity from its outer atmosphere with an effective temperature of 26,500 K, giving it the intense blue-white glow of a B-type star. It is only 11 million years of age.