45 Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 40m 43.31286s[1] |
| Declination | –00° 37′ 16.6538″[1] |
| Apparent magnitude (V) | 5.656[2] |
| Characteristics | |
| Spectral type | A3 IV[3] |
| U−B color index | +0.09[2] |
| B−V color index | +0.11[2] |
| Astrometry | |
| Radial velocity (Rv) | -46[4] km/s |
| Proper motion (μ) | RA: 8.42[1] mas/yr Dec.: 23.05[1] mas/yr |
| Parallax (π) | 9.26 ± 0.70 mas[1] |
| Distance | 350 ± 30 ly (108 ± 8 pc) |
| Orbit[5] | |
| 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 | |
| Rotational velocity (v sin i) | 75[6] km/s |
| Other designations | |
45 Aquilae is the Flamsteed designation for a triple star system in the equatorial constellation of Aquila. It is located 350 light-years (110 parsecs) away from Earth, give or take a 30 light-year margin of error, and has an apparent visual magnitude of 5.7.[2]
Based upon a stellar classification of A3 IV,[3] the primary component of this system is a subgiant star that is in the process of evolving away from the main sequence. 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.[8]
References
- ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
{{citation}}: Unknown parameter|month=ignored (help) - ^ 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.
- ^ 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.
- ^ Wilson, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode:1953QB901.W495......
- ^ 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.
- ^ Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943.
- ^ "45 Aql -- Star in double system", 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.
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