| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 18h44m 49.93813s[1] |
| Declination | +02° 03′ 36.1381″[1] |
| Apparent magnitude (V) | 5.02[2] |
| Characteristics | |
| Spectral type | B9 V[3] |
| B−V color index | −0.055±0.016[2] |
| Astrometry | |
| Radial velocity (Rv) | −13.0±4.2[4] km/s |
| Proper motion (μ) | RA: +9.347[1] mas/yr Dec.: −14.719[1] mas/yr |
| Parallax (π) | 6.7299 ± 0.2433 mas[1] |
| Distance | 480 ± 20 ly (149 ± 5 pc) |
| Absolute magnitude (MV) | −0.75[2] |
| Details | |
| Mass | 3.60±0.06[5] M☉ |
| Radius | 3.00[6] R☉ |
| Luminosity | 294+20.4 −20.9[5] L☉ |
| Surface gravity (log g) | 3.46±0.10[7] cgs |
| Temperature | 10,965+50 −51[5] K |
| Rotational velocity (v sin i) | 259[5] km/s |
| Other designations | |
4 Aql, AG+02 2306, BD+01° 3766, GC 25652, HD 173370, HIP 91975, HR 7040, SAO 123879[8] | |
| Database references | |
| SIMBAD | data |
4 Aquilae, abbreviated 4 Aql, is a single,[9] white-hued star in the equatorial constellationofAquila. 4 Aquilae is the Flamsteed designation. It has an apparent visual magnitude of 5.02,[2] making it a faint star visible to the naked eye. The distance to 4 Aql can be estimated from its annual parallax shiftof6.7 mas,[1] yielding an estimated range of around 480 light years. It is moving closer to the Earth with a heliocentric radial velocity of −13 km/s.[4]
This is a B-type main-sequence star with a stellar classification of B9 V.[3] It was classed as a Be starbyArne Sletteback in 1982, indicating it has ionized circumstellar gas.[6] The star is spinning rapidly, showing a projected rotational velocity of 259 km/s,[5] and is being viewed almost equator-on.[7] It has 3.6[5] times the mass of the Sun and 3[6] times the Sun's radius. The star is radiating 294[5] times the Sun's luminosity from its photosphere at an effective temperature of 10,965 K.[5]
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