The binary system consists of abright giant orbited by adwarf companion once every fourmillennia or so.[14] The companion is about 11 magnitudes fainter than the primary star,[15] and the two are separated by4.2″.[10]
Beta Draconis lies on or near thecepheid instability strip,[23] yet only appears to be a microvariable with a range of about 1/100 of a magnitude.[24][25] It was confirmed as a variable star with a range of about 1/100 of a magnitude by Gabriel Cristian Neagu using data from the TESS and Hipparcos missions.[24][25] The variability was reported to the AAVSO (American Association of Variable Star Observers), in the Variable Star Index.[26]
It bore the traditional nameRastaban, which has also been used forGamma Draconis.[14][28] This name, less commonly writtenRastaben, derives from theArabic phrasera's ath-thu'ban "head of the serpent/dragon". It was also known asAsuia andAlwaid/ælˈweɪd/,[29] the latter from the Arabical-ʽawāʼidh "the old mother camels".[29] In 2016, the IAU organized aWorking Group on Star Names (WGSN)[30] to catalogue and standardize proper names for stars. The WGSN approved the nameRastaban for the component Beta Draconis A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[11]
InChinese,天棓 (Tiān Bàng), meaningCelestial Flail, refers to an asterism consisting of Beta Draconis, Xi Draconis, Nu Draconis, Gamma Draconis andIota Herculis.[31] Consequently, theChinese name for Beta Draconis itself is known as天棓三 (Tiān Bàng sān, English:the Third Star of Celestial Flail).[28][32][33]
^Kovtyukh, V. V.; et al. (April 2005). "On the lithium abundance in F-, G-supergiants and its possible correlation with rotation".Kinematika I Fizika Nebesnykh Tel.21 (2):141–148.Bibcode:2005KFNT...21..141K.
^Skinner, S. L.; Brown, A. (1996). "ASCA X-ray spectra of late-type giants and supergiants: the active G star Beta Draconis (G2Ib - II)". In Pallavicini, Roberto; Dupree, Andrea K. (eds.).Cool stars; stellar systems; and the sun; Proceedings of the 9th Cambridge workshop; held 3-6 October 1995 in Florence; Italy. Astronomical Society of the Pacific Conference Series. Vol. 109. San Francisco: Astronomical Society of the Pacific (ASP). p. 291.Bibcode:1996ASPC..109..291S.
^Brown, A.; et al. (August 1984). "High-resolution, far-ultraviolet study of beta Draconis (G2 Ib-II) : transition region structure and energy balance".Astrophysical Journal.283:731–744.Bibcode:1984ApJ...283..731B.doi:10.1086/162358.
^abRicker, George R.; et al. (2014). Oschmann, Jacobus M.; Clampin, Mark; Fazio, Giovanni G.; MacEwen, Howard A. (eds.). "Transiting Exoplanet Survey Satellite (TESS)".Space Telescopes and Instrumentation 2014: Optical. Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave.9143: 914320.arXiv:1406.0151.Bibcode:2014SPIE.9143E..20R.doi:10.1117/12.2063489.hdl:1721.1/97916.S2CID54001919.
^abESA (1997). "The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission".Esa Special Publication.1200. ESA.Bibcode:1997ESASP1200.....E.
^"bet Dra".The International Variable Star Index. American Association of Variable Star Observers. Retrieved2020-01-11.
^Hessman, F. V.; et al. (December 2010). "On the naming convention used for multiple star systems and extrasolar planets".arXiv:1012.0707 [astro-ph.SR].
^abKunitzsch, 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.ISBN978-1-931559-44-7.
