21 Aquilae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 13m 42.70359s[1] |
| Declination | +02° 17′ 37.3403″[1] |
| Apparent magnitude (V) | 5.140[2] |
| Characteristics | |
| Spectral type | B8 II-III[3] |
| U−B color index | –0.399[2] |
| B−V color index | –0.065[2] |
| Variable type | α2 CVn |
| Astrometry | |
| Radial velocity (Rv) | –5.2[4] km/s |
| Proper motion (μ) | RA: +6.95[1] mas/yr Dec.: –3.28[1] mas/yr |
| Parallax (π) | 4.59 ± 0.29[1] mas |
| Distance | 710 ± 40 ly (220 ± 10 pc) |
| Details | |
| Radius | 4.3[5] R☉ |
| Surface gravity (log g) | 3.27[3] cgs |
| Temperature | 13,175[3] K |
| Metallicity [Fe/H] | –0.14[3] dex |
| Other designations | |
21 Aquilae (abbreviated 21 Aql) is a star in the equatorial constellation of Aquila. 21 Aquilae is its Flamsteed designation. Its apparent magnitude is 5.14[2] and it is located at a distance of around 710 light-years (220 parsecs) from Earth, give or take a 40 light-year margin of error.[1] The stellar classification of this star is B8 II-III,[3] with the luminosity class of II-III suggesting that the spectrum displays elements of both a giant star and a bright giant. The outer atmosphere has an effective temperature of 13,175 K;[3] this searing heat gives it the blue-white glow of a B-type star.[7]
References
- 1 2 3 4 5 6 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 4 Stepien, K. (December 1968), "Photometric behavior of magnetic stars", Astrophysical Journal, 154: 945, Bibcode:1968ApJ...154..945S, doi:10.1086/149815.
- 1 2 3 4 5 6 Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x.
- ↑ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
- ↑ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
- ↑ "V1288 Aql -- Variable Star of alpha2 CVn type", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-26.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16
External links
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