45 Aquilae, abbreviated 45 Aql, is a triple star system in the equatorial constellation of Aquila. 45 Aquilae is its Flamsteed designation. It is located 350 light-years (110 parsecs) away from Earth, give or take a 6 light-year margin of error, and has a combined apparent visual magnitude of 5.7.[2] The system is moving closer to the Earth with a heliocentric radial velocity of -46 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 40m 43.31912s[1] |
| Declination | –00° 37′ 16.3868″[1] |
| Apparent magnitude (V) | 5.656[2] (5.9 + 7.6)[3] |
| Characteristics | |
| Spectral type | A3 IV[4] |
| U−B color index | +0.09[2] |
| B−V color index | +0.11[2] |
| Astrometry | |
| Radial velocity (Rv) | -46[5] km/s |
| Proper motion (μ) | RA: +15.683[1] mas/yr Dec.: +5.323[1] mas/yr |
| Parallax (π) | 9.3151 ± 0.1561 mas[1] |
| Distance | 350 ± 6 ly (107 ± 2 pc) |
| Absolute magnitude (MV) | 0.49[6] |
| Orbit[7] | |
| Primary | 5 Aql Aa |
| Companion | 5 Aql Ab |
| Period (P) | 20.31 ± 0.17 yr |
| Semi-major axis (a) | 0.0850 ± 0.0020″ |
| Eccentricity (e) | 0.054 ± 0.047 |
| Inclination (i) | 158.3 ± 7.9° |
| Longitude of the node (Ω) | 202.0 ± 15.0° |
| Periastron epoch (T) | 1996.06 ± 0.92 |
| Argument of periastron (ω) (secondary) | 346.0 ± 25.0° |
| Details | |
| 45 Aql Aa | |
| Mass | 2.63±0.10[8] M☉ |
| Luminosity | 75.8+13.8 −11.7[8] L☉ |
| Temperature | 9,016+167 −165[8] K |
| Rotational velocity (v sin i) | 75[8] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Based upon a stellar classification of A3 IV,[4] the primary component of this system is a subgiant star that is in the process of evolving away from the main sequence. The star has 2.6[8] times the mass of the Sun and is spinning with a projected rotational velocity of 75 km/s.[8] It has an orbiting companion with a period of 20.31 years and an eccentricity of 0.054. At an angular separation of 42.2 arcseconds from this pair is a 12.7 magnitude tertiary companion.[10]
References
edit- ^ a b c d e 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.
- ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- ^ Malkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy and Astrophysics, 546: 5, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774, A69.
- ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- ^ a b Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- ^ 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.
- ^ Mason, Brian D.; Hartkopf, William I.; Tokovinin, Andrei (September 2010), "Binary Star Orbits. IV. Orbits of 18 Southern Interferometric Pairs", The Astronomical Journal, 140 (3): 735–743, Bibcode:2010AJ....140..735M, doi:10.1088/0004-6256/140/3/735.
- ^ a b c d e f 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.
- ^ "* 45 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-26.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.