Upsilon Aquilae
Star in the constellation Aquila
From Wikipedia, the free encyclopedia
Upsilon Aquilae is a star in the equatorial constellation of Aquila. Its name is a Bayer designation that is Latinized from υ Aquilae, and abbreviated Upsilon Aql or υ Aql. With an apparent visual magnitude of +5.91[6] it is a faint star but, according to the Bortle Dark-Sky Scale, it is visible to the naked eye from suburban skies. It has an annual parallax shift of 18.9 mas,[10] indicating a distance of 173 light-years (53 parsecs). The star is drifting closer with a radial velocity of −30 km/s.[7]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aquila[1] |
| Right ascension | 19h 45m 39.947s[2] |
| Declination | +07° 36′ 47.37″[2] |
| Apparent magnitude (V) | +5.889[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2][4] |
| Spectral type | A3 IV[5] |
| U−B color index | +0.09[6] |
| B−V color index | +0.18[6] |
| Astrometry | |
| Radial velocity (Rv) | −29.9±2.0[7] km/s |
| Proper motion (μ) | RA: +53.593 mas/yr[2] Dec.: −0.223 mas/yr[2] |
| Parallax (π) | 18.884±0.0408 mas[2] |
| Distance | 172.7 ± 0.4 ly (53.0 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.24[1] |
| Details | |
| Mass | 1.68[8] M☉ |
| Luminosity | 10.5[1] L☉ |
| Surface gravity (log g) | 4.21[3] cgs |
| Temperature | 7,906[3] K |
| Metallicity [Fe/H] | −0.05[3] dex |
| Rotational velocity (v sin i) | 22.5[8] km/s |
| Age | 361±308[8] Myr |
| Other designations | |
| υ Aql, 49 Aquilae, BD+07°4210, GC 27342, HD 186689, HIP 97229, HR 7519, SAO 125032, PPM 168596[9] | |
| Database references | |
| SIMBAD | data |
This is a subgiant star with a stellar classification of A3 IV.[5] The outer atmosphere is radiating energy into space with 10.5[1] times the Sun's luminosity from its photosphere at an effective temperature of 7,906 K,[3] which gives it the white-hot glow of an A-type star. It is 361 million years old with 1.68 times the mass of the Sun and has a relatively high rate of spin with a projected rotational velocity of 22.5 km/s. An infrared excess has been reported, although no circumstellar disk has been resolved.[8]