Its two components are designated Beta Aquilae A (formally named Alshain/ælˈʃeɪn/, the traditional name for the system)[13][14] and B.
Nomenclatureedit
β Aquilae (Latinised to Beta Aquilae) is the system's Bayer designation. The designations of the two components as Beta Aquilae A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[15]
The system bore the traditional name Alshain derived from the Perso-Arabic term الشاهين, aš-šāhīn, meaning "the (peregrine) falcon", perhaps by folk etymology from the Persianšāhīn tarāzū (or possibly šāhīn tara zed; see Gamma Aquilae), the Persian name for the asterismα, β and γ Aquilae.[citation needed] In 2016, the IAU organized a Working Group on Star Names (WGSN)[16] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[17] It approved the name Alshain for the component Beta Aquilae A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[14]
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Unuk al Ghyrab (عنق ألغراب - únuq al-ghuraab), which was translated into Latin as Collum Corvi, meaning the crow's neck.[18]
The primary, component A, is of magnitude 3.71 and spectral class G8IV. It has a very low level of surface magnetic activity and may be in a state similar to a Maunder minimum.[21] The activity shows a cycle of 969±27 d.[10] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[22] This is an aging subgiant star that has exhausted the supply of hydrogen at its core and is evolving into a giant.[10] It has a mass 26% greater than the Sun's,[9] a luminosity six times that of the Sun, and a radius about thrice solar.[8]
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^ abMontes, D.; et al. (September 2018), "Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K-primaries - I: High-resolution spectroscopy with HERMES: stellar parameters, abundances, and kinematics", Monthly Notices of the Royal Astronomical Society, 479 (1): 1332–1382, arXiv:1805.05394, Bibcode:2018MNRAS.479.1332M, doi:10.1093/mnras/sty1295.
^ abOja, T. (August 1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–4, Bibcode:1986A&AS...65..405O.
^ abJofré, E.; et al. (February 2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: 46, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, S2CID 53666931, A50.
^ abRains, Adam D.; et al. (April 2020), "Precision angular diameters for 16 southern stars with VLTI/PIONIER", Monthly Notices of the Royal Astronomical Society, 493 (2): 2377–2394, arXiv:2004.02343, Bibcode:2020MNRAS.493.2377R, doi:10.1093/mnras/staa282, S2CID 214802418
^ abBruntt, H.; et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society, 405 (3): 1907–1923, arXiv:1002.4268, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x, S2CID 118495267
^ abcButkovskaya, Varvara; et al. (February 2018), "Long-term stellar magnetic field study at the Crimean Astrophysical Observatory", Long-term Datasets for the Understanding of Solar and Stellar Magnetic Cycles, Proceedings of the International Astronomical Union, IAU Symposium, vol. 340, pp. 35–38, Bibcode:2018IAUS..340...35B, doi:10.1017/S1743921318001035, S2CID 125610540.
^Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785, S2CID 27151456
^Fuhrmann, K.; et al. (February 2017), "Multiplicity among Solar-type Stars", The Astrophysical Journal, 836 (1): 23, Bibcode:2017ApJ...836..139F, doi:10.3847/1538-4357/836/1/139, 139.
^Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
^ ab"Naming Stars". IAU.org. Retrieved 3 March 2018.
^Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
^"WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
^Knobel, E. B. (June 1895). "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket". Monthly Notices of the Royal Astronomical Society. 55: 429–438. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.
^(in Chinese)中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
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^Andretta, V.; et al. (February 2005), "The Ca II Infrared Triplet as a stellar activity diagnostic . I. Non-LTE photospheric profiles and definition of the RIRT indicator", Astronomy and Astrophysics, 430 (2): 669–677, Bibcode:2005A&A...430..669A, doi:10.1051/0004-6361:20041745.
^Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, archived from the original on 2019-06-25, retrieved 2012-02-04
^Bonfils, Xavier; Delfosse, Xavier; Udry, Stéphane; Santos, Nuno C.; Forveille, Thierry; Ségransan, Damien (2005). "Metallicity of M dwarfs. I. A photometric calibration and the impact on the mass-luminosity relation at the bottom of the main sequence". Astronomy and Astrophysics. 442 (2): 635–642. arXiv:astro-ph/0503260. Bibcode:2005A&A...442..635B. doi:10.1051/0004-6361:20053046. S2CID 13900901.
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External linksedit
Kaler, James B., "ALSHAIN (Beta Aquilae)", Stars, University of Illinois, retrieved 2018-03-03