71 Aquilae

"l Aquilae" redirects here. Not to be confused with Lambda Aquilae or L'Aquila.
71 Aquilae
Location of 71 Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 20h 38m 20.28206s[1]
Declination −01° 06′ 18.4311″[1]
Apparent magnitude (V) 4.33[2]
Characteristics
Spectral type G8 III[3]
U−B color index +0.68[2]
B−V color index +0.96[2]
R−I color index 0.46
Astrometry
Radial velocity (Rv)-5.6[4] km/s
Proper motion (μ) RA: +14.84[1] mas/yr
Dec.: -16.45[1] mas/yr
Parallax (π)9.67 ± 0.75 mas[1]
Distance340 ± 30 ly
(103 ± 8 pc)
Absolute magnitude (MV)–1.03[5]
Orbit[6]
Period (P)205.2 days
Semi-major axis (a)3.82 ± 0.81 mas
Eccentricity (e)0.000
Inclination (i)147.70° ± 5.90°
Longitude of the node (Ω)314.00 ± 1.30°
Periastron epoch (T)2423358.0 HJD
Argument of periastron (ω)
(secondary)		0.00°
Details
Surface gravity (log g)2.87[7] cgs
Temperature5,060[7] K
Metallicity [Fe/H]–0.13[7] dex
Rotational velocity (v sin i)10[8] km/s
Other designations
BD-01 4016, HD 196574, HIP 101847, HR 7884, SAO 144649.[9]
Database references
SIMBADdata

71 Aquilae (abbreviated 71 Aql) is a binary star in the equatorial constellation of Aquila. 71 Aquilae is its Flamsteed designation though it also bears the Bayer designation l Aquilae. The apparent visual magnitude of the system is 4.33,[2] making it bright enough to be viewed by the naked eye. It has an annual parallax shift of 9.67 mas,[1] which equates to a physical distance of 340 light-years (100 parsecs) from Earth, give or take a 30 light-year margin of error. At this distance, the brightness of the system is diminished by 0.065 in visual magnitude from extinction caused by interstellar gas and dust.[5]

This is a spectroscopic binary system where the presence of an orbiting companion is revealed by shifts in the spectral lines caused by the Doppler effect. The primary component is a giant star with a stellar classification of G8 III.[3] The secondary is following a circular orbit with a period of 205.2 days.[6]

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  6. ^ a b Cite error: The named reference aaa442_1_365 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference apjss74 was invoked but never defined (see the help page).
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  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).