Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquila |
Right ascension | 19h 20m 32.90437s [1] |
Declination | –05° 24′ 56.7440″ [1] |
Apparent magnitude (V) | 5.00 [2] |
Characteristics | |
Spectral type | G8 III-IV [3] |
U−B color index | +0.634 [2] |
B−V color index | +0.936 [2] |
R−I color index | 0.5 |
Astrometry | |
Radial velocity (Rv) | −16.91±1.93 [4] km/s |
Proper motion (μ) |
RA: +113.13
[1]
mas/
yr Dec.: +46.20 [1] mas/ yr |
Parallax (π) | 21.15 ± 0.39 mas [1] |
Distance | 154 ± 3
ly (47.3 ± 0.9 pc) |
Orbit [4] | |
Period (P) | 266.544 days |
Eccentricity (e) | 0.833 |
Semi-amplitude (K1) (primary) | 29.86 km/s |
Details | |
26 Aquilae A | |
Mass | 3.2+0.2 −0.2 [5] M☉ |
Radius | 6 [4] R☉ |
Luminosity | 21 [4] L☉ |
Surface gravity (log g) | 3.2 [4] cgs |
Temperature | 4940 [5] K |
Metallicity [Fe/H] | –0.21 [4] dex |
Rotational velocity (v sin i) | 1.3 [4] km/s |
26 Aquilae B | |
Mass | 1.4±0.05 [5] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
26 Aquilae (abbreviated 26 Aql) is a binary star system in the equatorial constellation of Aquila. 26 Aquilae is its Flamsteed designation though it also bears the Bayer designation f Aquilae. It has an apparent visual magnitude of 5.00, [2] which means it is faintly visible to the naked eye. As the Earth orbits the Sun, this star system undergoes a parallax shift of 21.15 mas. [1] This means it is located at a distance of approximately 154 light-years (47 parsecs) from Earth, give or take a three-light-year margin of error.
This is a single-lined spectroscopic binary system, meaning that the presence of an orbiting companion is revealed through shifts in the spectrum of the primary star. The pair orbit each other with a period of 266.544 days at a high eccentricity of 0.833. [4] Little is known about this companion, although its mass can be estimated as 140% of the Sun's.
The primary component has a stellar classification of G8 III-IV. [3] The luminosity class of III-IV indicates the spectrum resembles that of a star part way between the subgiant and giant stages of its evolution. It has more than three [5] times the mass of the Sun and six [4] times the Sun's radius. It is radiating 21 [4] times as much luminosity as the Sun from this enlarged outer envelope at an effective temperature of 4,940 K. [5] At this heat, the star glows with the characteristic yellow hue of a G-type star. [7]