4 Aquilae

4 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 18h 44m 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]
Distance480 ± 20 ly
(149 ± 5 pc)
Absolute magnitude (MV)−0.75[2]
Details
Mass3.60±0.06[5] M☉
Radius3.00[6] R☉
Luminosity294+20.4
−20.9[5] L☉
Surface gravity (log g)3.46±0.10[7] cgs
Temperature10,965+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
SIMBADdata

4 Aquilae, abbreviated 4 Aql, is a single,[9] white-hued star in the equatorial constellation of Aquila. 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 shift of 6.7 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 star by Arne 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]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  5. ^ a b c d e f g h Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Silaj2014 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Lefever2010 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference chini2012 was invoked but never defined (see the help page).