  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila[1] |
| Right ascension | 19h 24m 58.19997s[2] |
| Declination | +11° 56′ 39.8885″[2] |
| Apparent magnitude (V) | 5.16[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G8 IV[3] |
| U−Bcolor index | +0.42[4] |
| B−Vcolor index | +0.77[3] |
| Astrometry | |
| Radial velocity (Rv) | −100.5[5] km/s |
| Proper motion (μ) | RA: +721.292[2]mas/yr Dec.: +642.968[2]mas/yr |
| Parallax (π) | 67.0153±0.0657 mas[2] |
| Distance | 48.67 ± 0.05 ly (14.92 ± 0.01 pc) |
| Absolute magnitude (MV) | +4.26[1] |
| Details | |
| Mass | 1.16±0.07[6] M☉ |
| Radius | 1.379±0.042[7] R☉ |
| Luminosity | 1.904±0.045[7] L☉ |
| Surface gravity (log g) | 4.18±0.03[6] cgs |
| Temperature | 5,510±90[3] K |
| Metallicity[Fe/H] | +0.37[8] dex |
| Age | 4.5±0.2[6] Gyr |
| Other designations | |
| BD+11 3833,FK5 1503,HD 182572,GJ 759,NLTT 47763,HIP 95447,HR 7373,LFT 1477,LHS 3463,LTT 15668,NSV 11994,SAO 104807.[9] | |
| Database references | |
| SIMBAD | data |
31 Aquilae (abbreviated31 Aql) is astar in theequatorialconstellation ofAquila.31 Aquilae is itsFlamsteed designation though it also bears theBayer designationb Aquilae. This star has anapparent visual magnitude of 5.16 and is 49.5 light years from Earth. It has no known companions.
31 Aquilae has anapparent visual magnitude of 5.16,[3] making it bright enough to be seen with the naked eye in dark skies. The annualparallax shift of67.0 mas[2] yields a distance estimate of 48.7light-years (14.9parsecs) from Earth. It is avariable star with a magnitude change of less than 0.02.[6]
With astellar classification of G8 IV,[3] theluminosity class of IV indicates this is asubgiant star. Compared to the Sun, it has 116%[6] of the mass and 138%[7] of the radius. It is radiating nearly double[7] the luminosity of the Sun from itsouter atmosphere at aneffective temperature of 5,510 K,[3] giving it the yellow hue of aG-type star.[10] Its age is probably similar toNGC 188, the oldest open cluster known, which was calculated to be over 5 billion years. For its age, it is surprisingly rich in elements other than hydrogen or helium, contrary to common assumptions that the oldest stars should bemetal-poor.
No certain substellar companion has been detected so far around 31 Aquilae.McDonald Observatory team has set limits to the presence of one or more planets[11] around 31 Aquilae with masses between 0.22 and 1.9Jupiter masses and average separations spanning between 0.05 and 5.2Astronomical Units.
The following stars areoptical companions that are coincidentally aligned near the line of sight to 31 Aquilae.
| Companion | HD 231345 | BD+11 3833C |
|---|---|---|
| Right ascension | 19h 24m 51.8595s | 19h 24m 50.8s |
| Declination | +11° 57′ 14.692″ | +11° 57′ 36″ |
| Magnitude | 8.56 | 10.6 |
| Spectral type | G0 | |
| Reference | Simbad | Simbad |
