Omicron Aquilae

Omicron Aquilae
Diagram showing star positions and boundaries of the Aquila constellation and its surroundings
Location of ο Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 51m 01.64400s[1]
Declination +10° 24′ 56.5992″[1]
Apparent magnitude (V) 5.11[2]
Characteristics
Spectral type F8 V + M3 V[3]
U−B color index 0.07
B−V color index 0.55[4]
R−I color index 0.29
Astrometry
Radial velocity (Rv)–0.2[5] km/s
Proper motion (μ) RA: +242.28[1] mas/yr
Dec.: –136.48[1] mas/yr
Parallax (π)52.11 ± 0.29 mas[1]
Distance62.6 ± 0.3 ly
(19.2 ± 0.1 pc)
Absolute magnitude (MV)3.71[5]
Details
ο Aql A
Mass1.252[6] M☉
Radius1.52[6] R☉
Surface gravity (log g)4.07[7] cgs
Temperature6,090[7] K
Metallicity [Fe/H]+0.07[7] dex
Rotational velocity (v sin i)3[4] km/s
Age3.3[5] Gyr
ο Aql C
Mass0.33[8] M☉
Other designations
54 Aquilae, ο Aquilae, BD+10 4073, GJ 768.1, HD 187691, HIP 97675, HR 7560, NLTT 48319, LTT 15798, SAO 1053380.[9]
Database references
SIMBADdata

Omicron Aquilae (ο Aql, ο Aquilae) is the Bayer designation for a double star in the equatorial constellation of Aquila. The brighter component has an apparent visual magnitude of +5.11,[2] which means it is faintly visible to the naked eye in dark suburban skies. The annual parallax shift of this star is 52.11 mas,[1] which is equivalent to a physical distance of 62.6 light-years (19.2 parsecs) from Earth.

The primary component, Omicron Aquilae A, is an F-type main sequence star with a stellar classification of F8 V.[3] It has about 125% of the mass of the Sun and 152% of the Sun's radius.[6] With an age of roughly 3.3 billion years,[5] it appears to spinning at a leisurely rate with a projected rotational velocity of 3 km/s.[4] The outer atmosphere has an effective temperature of 6,090 K,[7] giving it the yellowish-white hue of an F-type star.

In 1998, Omicron Aquilae was one of nine stars identified as experiencing a superflare. The first flare observed from Omicron Aquilae was in 1979, with a magnitude increase of 0.07 and a duration of less than five days. The second occurred in 1980, with a magnitude change of 0.09 and a duration of fifteen days. The energy released during the second flare is estimated as 9 × 1037 erg.[10]

There is a magnitude 12.67 common proper motion companion located at an angular separation of 22.5 arcseconds along a position angle of 221°. Based upon its matching parallax value, this corresponds to a projected separation of 431 astronomical units. (Hence, the companion is located at this separation or greater.) Designated component C, this is a small red dwarf star with a stellar classification of M3 V. Component B is an optical companion that appears near the primary only through a chance alignment.[3]

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