Astronomy:4 Aquilae
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas |
| 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 | |
| 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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode: 1999MSS...C05....0H.
- ↑ 4.0 4.1 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, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ 6.0 6.1 6.2 Silaj, J. et al. (November 2014), "The Hα Profiles of Be Shell Stars", The Astrophysical Journal 795 (1): 12, doi:10.1088/0004-637X/795/1/82, 82, Bibcode: 2014ApJ...795...82S.
- ↑ 7.0 7.1 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, doi:10.1051/0004-6361/200911956, Bibcode: 2010A&A...515A..74L.
- ↑ "4 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=4+Aql.
- ↑ 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, doi:10.1111/j.1365-2966.2012.21317.x, Bibcode: 2012MNRAS.424.1925C.
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