QS Aquilae

QS Aquilae is a triple star system consisting of an eclipsing binary in a 2.5 day orbit around which a third star orbits in 77 years.[2] It is located in the constellation Aquila and is barely visible to the naked eye.

QS Aquilae

Observation data Epoch J2000      Equinox J2000
Constellation	Aquila
Right ascension	19^h 41^m 05.528^s[1]
Declination	+13° 48′ 56.45″[1]
Apparent magnitude (V)	5.988
Characteristics
Spectral type	B5V
U−B color index	−0.52
B−V color index	−0.08
Variable type	Eclipsing binary[2]
Astrometry
Radial velocity (Rv)	−14.2 ± 2 km/s
Proper motion (μ)	RA: −0.04 ± 0.60[1] mas/yr Dec.: −11.47 ± 0.43[1] mas/yr
Parallax (π)	0.49 ± 0.62[1] mas
Orbit[2]
Primary	QS Aquilae AB (eclipsing pair)
Companion	QS Aquilae C
Period (P)	77.0±4.3 yr
Semi-major axis (a)	0.111±0.045″
Eccentricity (e)	0.947±0.038
Inclination (i)	61.2±3.6°
Longitude of the node (Ω)	144.5±5.1°
Periastron epoch (T)	1962.3±2.3
Argument of periastron (ω) (secondary)	336.8±4.7°
Orbit[2]
Primary	QS Aquilae A
Companion	QS Aquilae B
Period (P)	2.5132987±0.0000075 d
Semi-major axis (a)	13.78±0.11 R⊙
Inclination (i)	83.6±1.3°
Semi-amplitude (K1) (primary)	73.98±0.33 km/s
Semi-amplitude (K2) (secondary)	201.76±2.09 km/s
Other designations
KUI 93, QS Aql, BD+13° 4098, HD 185936, HIP 96840, HR 7486, WDS J19411+1349, 2MASS J19410553+1348565[3]
Database references
SIMBAD	data

References

1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.Vizier catalog entry
2. Zasche, P.; et al. (2017). "V773 Cas, QS Aql, and BR Ind: Eclipsing Binaries as Parts of Multiple Systems". The Astronomical Journal. 153 (1). 36. arXiv:1701.02537. Bibcode:2017AJ....153...36Z. doi:10.3847/1538-3881/153/1/36.
3. "QS Aquilae". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-03-08.