31 Aquilae
Location of 31 Aquilae (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila[1] |
| Right ascension | 19h 24m 58.20027s[2] |
| Declination | +11° 56′ 39.8862″[2] |
| Apparent magnitude (V) | 5.16[3] |
| Characteristics | |
| Spectral type | G8 IV[3] |
| U−B color index | +0.42[4] |
| B−V color index | +0.77[3] |
| Astrometry | |
| Radial velocity (Rv) | −100.5[5] km/s |
| Proper motion (μ) | RA: +721.02[2] mas/yr Dec.: +642.49[2] mas/yr |
| Parallax (π) | 65.89±0.26 mas[2] |
| Distance | 49.5 ± 0.2 ly (15.18 ± 0.06 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 (abbreviated 31 Aql) is a star in the equatorial constellation of Aquila. 31 Aquilae is its Flamsteed designation though it also bears the Bayer designation b Aquilae. This star has an apparent visual magnitude of 5.16 and is 49.5 light years from Earth. It has no known companions.
Properties
[edit | edit source]31 Aquilae has an apparent visual magnitude of 5.16,[3] making it bright enough to be seen with the naked eye in dark skies. The annual parallax shift of 65.89 mas[2] yields a distance estimate of 49.5 light-years (15.2 parsecs) from Earth. It is a variable star with a magnitude change of less than 0.02.[6]
With a stellar classification of G8 IV,[3] the luminosity class of IV indicates this is a subgiant 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 its outer atmosphere at an effective temperature of 5,510 K,[3] giving it the yellow hue of a G-type star.[10] Its age is probably similar to NGC 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 be metal-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 1.9 Jupiter masses and average separations spanning between 0.05 and 5.2 Astronomical Units.
Optical companions
[edit | edit source]The following stars are optical 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 |
References
[edit | edit source]- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f g Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). See Table 13.
- ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). See Table 10.
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Detection Limits from the McDonald Observatory Planet Search Program
External links
[edit | edit source]- The Old Disk Metal-Rich Subgiant 31 Aquilae Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- Image 31 Aquilae
- HR 7373
- CCDM 19249+1157
- R.A. Wittenmeyer et al., "Detection Limits from the McDonald Observatory Planet Search Program", The Astronomical Journal, Volume 132, Issue 1, pp. 177–188, May 2006.
