Upsilon Aquilae

Not to be confused with U Aquilae.

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^[5] 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,^[9] indicating a distance of 173 light-years (53 parsecs). The star is drifting closer with a radial velocity of −30 km/s.^[6]

Upsilon Aquilae

Location of υ Aquilae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Aquila[1]
Right ascension	19h 45m 39.947s[2]
Declination	+07° 36′ 47.37″[2]
Apparent magnitude (V)	+5.889[3]
Characteristics
Spectral type	A3 IV[4]
U−B color index	+0.09[5]
B−V color index	+0.18[5]
Astrometry
Radial velocity (Rv)	−29.9±2.0[6] 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[7] 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[7] km/s
Age	361±308[7] Myr
Other designations
υ Aql, 49 Aquilae, BD+07°4210, GC 27342, HD 186689, HIP 97229, HR 7519, SAO 125032, PPM 168596[8]
Database references
SIMBAD	data

This is a subgiant star with a stellar classification of A3 IV.^[4] 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.^[7]