18 Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 06m 58.60289s[1] |
| Declination | +11° 04′ 16.4173″[1] |
| Apparent magnitude (V) | 5.072 |
| Characteristics | |
| Spectral type | B8 III[2] |
| U−B color index | -0.44[3] |
| B−V color index | -0.08[3] |
| Variable type | Ellipsoidal Variable |
| Astrometry | |
| Radial velocity (Rv) | -18.6[4] km/s |
| Proper motion (μ) | RA: -0.89[1] mas/yr Dec.: -32.11[1] mas/yr |
| Parallax (π) | 6.43 ± 0.79[1] mas |
| Distance | approx. 510 ly (approx. 160 pc) |
| Details | |
| Rotational velocity (v sin i) | 50[2] km/s |
| Other designations | |
18 Aquilae (abbreviated 18 Aql) is a triple star[6] system in the constellation of Aquila. 18 Aquilae is the Flamsteed designation; it also bears the variable star designation Y Aquilae. It has an apparent visual magnitude of 5.07. The distance to this system can be estimated from the annual parallax shift of 6.43 mas, yielding a value of around 510 light-years (160 parsecs) away from Earth.
The inner pair of stars in this system form a spectroscopic binary with a combined magnitude of 5.44 and an orbital period of 1.302 days. The primary component is a giant star with a stellar classification of B8 III.[2] Because the orbital plane is inclined near the line of sight, two form an eclipsing binary system. The eclipse of the primary component causes a 0.04 drop in magnitude, while the eclipse of the secondary results in a decrease of 0.03.[7] At an angular separation of 0.310 arcseconds is the magnitude 6.39 tertiary component.[6] This system has a high peculiar velocity of 29.7 ± 3.9 km/s relative to the neighboring stars.[8]
References
- 1 2 3 4 5 van Leeuwen, F. (November 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.
- 1 2 3 Levato, H. (January 1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics, Supplemental Series 19: 91–99, Bibcode:1975A&AS...19...91L.
- 1 2 Osawa, K.; Hata, S. (1962), "Three-color photometry of B8-A2 stars (II).", Annals of the Tokyo Astronomical Observatory 7: 209, Bibcode:1962AnTok...7..209O.
- ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institution of Washington. Bibcode:1953QB901.W495.....
- ↑ "18 Aql -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-25.
- 1 2 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.
- ↑ Malkov, O. Yu.; et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics 446 (2): 785–789, Bibcode:2006A&A...446..785M, doi:10.1051/0004-6361:20053137.
- ↑ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
External links
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