Omicron Aquilae
Star in the constellation Aquila
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Omicron Aquilae is a double star in the equatorial constellation of Aquila. Its name is a Bayer designation that is Latinized from ο Aquilae, and abbreviated Omicron Aql or ο Aql. 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 51.3 mas,[1] which is equivalent to a physical distance of 63.6 light-years (19.5 parsecs) from Earth.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 51m 01.644s[1] |
| Declination | +10° 24′ 56.59″[1] |
| Apparent magnitude (V) | 5.11[2] |
| Characteristics | |
| Spectral type | F8 V + M3 V[3] |
| U−B color index | 1.486[4] |
| B−V color index | 0.55[5] |
| R−I color index | 0.29[citation needed] |
| Astrometry | |
| Radial velocity (Rv) | 0.036±0.0003[6] km/s |
| Proper motion (μ) | RA: +241.713 mas/yr[1] Dec.: −136.695 mas/yr[1] |
| Parallax (π) | 51.3133±0.0898 mas[1] |
| Distance | 63.6 ± 0.1 ly (19.49 ± 0.03 pc) |
| Absolute magnitude (MV) | 3.71[7] |
| Details | |
| ο Aql A | |
| Mass | 1.25±0.01[8] M☉ |
| Radius | 1.48±0.03[4] R☉ |
| Luminosity | 2.79±0.13[4] L☉ |
| Surface gravity (log g) | 4.30±0.02[8] cgs |
| Temperature | 6176±9[8] K |
| Metallicity [Fe/H] | +0.137±0.007[8] dex |
| Rotational velocity (v sin i) | 3[5] km/s |
| Age | 3.30+0.07 −0.20[8] Gyr |
| ο Aql B | |
| Mass | 0.33[9] M☉ |
| Radius | 0.37[10] R☉ |
| Luminosity | 0.015[10] L☉ |
| Surface gravity (log g) | 4.86[10] cgs |
| Temperature | 3,338[10] K |
| Other designations | |
| ο Aquilae, 54 Aquilae, BD+10 4073, GC 27480, GJ 768.1, GJ 9671, HD 187691, HIP 97675, HR 7560, SAO 1053380, PPM 137097, ADS 13012, WDS J19510+1025A, LTT 15798, NLTT 48319[11] | |
| Database references | |
| SIMBAD | data |
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[8] and 148% of the Sun's radius. With an age of roughly 3.3 billion years,[8] it appears to spinning at a leisurely rate with a projected rotational velocity of 3 km/s.[5] The outer atmosphere has an effective temperature of 6,123 K,[4] 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.[12]
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.) This is confusingly designated WDS J19510+1025C or ο Aquilae B. It is a small red dwarf star with a stellar classification of M3 V. A third star, a magnitude fainter and slightly closer to the primary, is an optical companion that appears near the primary only through a chance alignment.[3]