21 Draconis, GJ 9584, BD+54° 1857, SAO 30239, HIP 83608
A: Alrakis, HR 6370, HD 154906
B: HR 6369, HD 154905
Database references
SIMBAD
μ Dra
μ Dra A
μ Dra B
Mu Draconis (μ Draconis, abbreviated Mu Dra, μ Dra) is a multiple star system near the head of the constellation of Draco. With a combined magnitude of 4.92,[2] it is visible to the naked eye. Based on parallax estimates by the Hipparcos spacecraft, it is located approximately 89 light-years from the Sun.[1]
The system consists of a single primary star (designated Mu Draconis A, officially named Alrakis/ælˈreɪkɪs/ from the traditional name of the system),[8][9] a secondary binary pair (Mu Draconis B) and a further single star (C). B's two components are designated Mu Draconis Ba and Bb.
Mu Draconis A and Ba are nearly identical F-type main-sequence stars, with masses of 1.35 M☉ and 1.30 M☉, respectively.[7] Both have the spectral class of F5V, and have similar apparent magnitude, at 5.66 and 5.69, respectively.[3] The secondary, Mu Draconis B, has a drifting radial velocity, and is itself a spectroscopic binary with an orbital period of 2,270 days.[10] The distance between both stars is 2 arcseconds, so a telescope with a diameter of at least 6 centimetres is necessary to see them separate. The smaller component, Mu Draconis Bb, has a mass of 0.2 M☉. Mu Draconis C is a 14th magnitude common-proper-motion companion 13.2" away from the bright pair, with a mass of 0.29 M☉.[7]
^ abcdefvan Leeuwen, F.; et al. (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. S2CID 18759600.
^ ab"* mu Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 May 2017.
^ abc"Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 16 May 2017.
^ abMermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data: 0. Bibcode:1986EgUBV........0M.
^Holmberg, J.; Nordström, B.; Andersen, J. (2007). "The Geneva-Copenhagen survey of the Solar neighbourhood II". Astronomy and Astrophysics. 475 (2): 519. arXiv:0707.1891. Bibcode:2007A&A...475..519H. doi:10.1051/0004-6361:20077221. S2CID 119054949.
^ abcHolmberg, J.; Nordström, B.; Andersen, J. (2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID 118577511.
^ abcdTokovinin, Andrei (2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal. 147 (4): 87. arXiv:1401.6827. Bibcode:2014AJ....147...87T. doi:10.1088/0004-6256/147/4/87. S2CID 56066740.
^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.
^"Naming Stars". IAU.org. Retrieved 16 December 2017.
^Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088. (SB9 catalog entry)
MuDraconis (μ Draconis, abbreviated Mu Dra, μ Dra) is a multiple star system near the head of the constellation of Draco. With a combined magnitude of...
Gamma Draconis (γ Draconis, abbreviated Gamma Dra, γ Dra), formally named Eltanin /ɛlˈteɪnɪn/, is a star in the northern constellation of Draco. Contrary...
Beta Draconis, a name Latinized from β Draconis, is a binary star system and the third-brightest star in the northern circumpolar constellation of Draco...
with MuDraconis, which was previously called al-Rāqis [arˈraːqis] in Arabic. In 1848, English astronomer John Russell Hind discovered that Mu Cephei...
Frank Herbert's works). Arrakis is also an alternative name for the star MuDraconis. The fictional desert planet of Tatooine in the Star Wars franchise was...
as a ring of mother camels – Beta Draconis (Rastaban), Gamma Draconis (Eltanin), Nu Draconis (Kuma) and Xi Draconis (Grumium) – surrounding a foal (the...
Xi Draconis (ξ Draconis, abbreviated Xi Dra, ξ Dra) is a double or binary star in the northern circumpolar constellation of Draco. It has an apparent visual...
Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak /ˈmɑːrfæk/ with...
Beta Muscae Binary star system 3.05 Mu Ursae Majoris Binary star system Suspected variable star 3.07 Delta Draconis Star 3.076 Zeta Arae Star 3.08 2.74...
Fomalhaut as it lies within a light-year of it. Of magnitude 6.5, it is a BY Draconis variable. The second-brightest star in the constellation, Epsilon Piscis...
(Johnson & Morgan 1953, Keenan & McNeil 1989). 61 Cygni A is a typical BY Draconis variable star designated as V1803 Cyg while 61 Cygni B is a flare type...
structure modeled as stratospheric. Iota Draconis b: The first planet discovered around the giant star Iota Draconis, an orange giant. This provides evidence...
Chicago Press. ISBN 978-0-226-73860-4. Shizhen, Li (2021-02-02). Ben Cao Gang Mu, Volume VIII. Oakland, California: University of California Press. ISBN 978-0-520-37991-6...
Protocol Psi Draconis Dziban Draco A single-star asterism in the Purple Forbidden enclosure. 柱史 Zhù Shǐ Official of Royal Archives Phi Draconis 钺 Yuè Battle...
needs confirmation. First known planet orbiting a giant star Iota Draconis b Iota Draconis 2002 Aldebaran b was announced in 1997, but was not confirmed until...
Global Information
