4 Aquilae

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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]
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 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]

References

  1. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 .
  2. 1 2 3 4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  3. 1 2 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
  4. 1 2 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv: 1606.08053 , Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID   119231169.
  5. 1 2 3 4 5 6 7 8 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv: 1201.2052 , Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID   55586789.
  6. 1 2 3 Silaj, J.; et al. (November 2014), "The Hα Profiles of Be Shell Stars", The Astrophysical Journal, 795 (1): 12, Bibcode:2014ApJ...795...82S, doi:10.1088/0004-637X/795/1/82, S2CID   120167606, 82.
  7. 1 2 Lefever, K.; et al. (June 2010), "Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satellite", Astronomy and Astrophysics, 515: A74, arXiv: 0910.2851 , Bibcode:2010A&A...515A..74L, doi:10.1051/0004-6361/200911956, S2CID   54028925.
  8. ↑ "4 Aql". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved October 27, 2018.
  9. ↑ Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925–1929, arXiv: 1205.5238 , Bibcode:2012MNRAS.424.1925C, doi: 10.1111/j.1365-2966.2012.21317.x , S2CID   119120749.
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