Pi Aquilae

Pi Aquilae, Latinised from π Aquilae, is the Bayer designation for a binary star[2] system in the equatorial constellation of Aquila, about 3° to the north of the bright star Altair.[3] The apparent visual magnitude of the system is 5.85,[2] making it faintly visible to the naked eye from dark suburban skies. Based upon an annual parallax shift of 6.34 mas, the distance to this system is roughly 510 light-years (160 parsecs).[1]

Pi Aquilae

Location of π Aquilae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Aquila
Right ascension	19h 48m 42.05765s[1]
Declination	+11° 48′ 57.2177″[1]
Apparent magnitude (V)	5.85 (6.47/6.75)[2]
Characteristics
Spectral type	G8 III: + A1 V[2][3]
Astrometry
Radial velocity (Rv)	+12.6[3] km/s
Proper motion (μ)	RA: +16.16[1] mas/yr Dec.: –10.60[1] mas/yr
Parallax (π)	6.34 ± 0.52 mas[1]
Distance	510 ± 40 ly (160 ± 10 pc)
Absolute magnitude (MV)	−0.22[4]
Details
Luminosity	108[4] L☉
Other designations
π Aql, 52 Aquilae, BD+11 3994, HIP 97473, HR 7544, SAO 105282[5]
A: HD 187259
B: HD 187260
Database references
SIMBAD	data
	A
	B

The binary nature of this system was first discovered by William Herschel in 1785.[3] The primary component of is a magnitude 6.47[2] giant star with a stellar classification of G8 III:.[2] A companion star at an angular separation of 1.437 arcseconds is an A-type main-sequence star with a classification of A1 V.[2] It is slightly fainter, with an apparent magnitude of 6.75.[2]