Beta Draconis

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β Draconis
Location of β Draconis (circled)
Observation data
ICRS
)
Constellation Draco
Right ascension 17h 30m 25.96170s[1]
Declination +52° 18′ 04.9993″[1]
Apparent magnitude (V) 2.79[2]
Characteristics
Spectral type G2Ib-IIa[3]
U−B color index +0.954±0.007[4]
B−V color index +0.98[5]
R−I color index +0.48[5]
Distance
380 ± 4 ly
(117 ± 1 pc)
Absolute magnitude (MV)–2.457[6]
Details
Myr
HR 6536, SAO 30429, ADS 10611, WDS 17304+5218AB[9]
Database references
SIMBADdata

Beta Draconis, a name

easily seen with the naked eye. Based upon parallax measurements from the Hipparcos astrometry satellite,[12][13] it lies at a distance of about 380 light-years (120 parsecs) from the Sun.[1] The system is drifting closer with a radial velocity of −21 km/s.[4]

The binary system consists of a

″.[10]

The

chromospheric emission that is generating X-ray[19][20] and far-UV radiation.[21] There is a detectable magnetic field with a longitudinal field strength of −1.16±0.25 G.[22]

Beta Draconis lies on or near the

cepheid instability strip,[23] yet only appears to be a microvariable with a range of about 1/100th of a magnitude.[24][25] It was confirmed as a variable star with a range of about 1/100th 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]

Nomenclature

β Draconis (Latinised to Beta Draconis) is the system's Bayer designation. The designations of the two components as Beta Draconis 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).[27]

It bore the traditional name Rastaban, which has also been used for Gamma Draconis.[14][28] This name, less commonly written Rastaben, derives from the Arabic phrase ra's ath-thu'ban "head of the serpent/dragon". It was also known as Asuia and Alwaid /ælˈweɪd/,[29] the latter from the Arabic al-ʽawāʼidh "the old mother camels".[29] In 2016, the IAU organized a Working Group on Star Names (WGSN)[30] to catalogue and standardize proper names for stars. The WGSN approved the name Rastaban 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]

Beta Draconis is part of the asterism of the Mother Camels (Arabic al'awa'id), along with Gamma Draconis (Eltanin), Mu Draconis (Erakis), Nu Draconis (Kuma) and Xi Draconis (Grumium), which was later known as the Quinque Dromedarii.[28]

In

Chinese name for Beta Draconis itself is known as 天棓三 (Tiān Bàng sān, English: the Third Star of Celestial Flail).[28][32][33]

References

  1. ^
    S2CID 18759600
    .
  2. ^
    S2CID 119096173
    .
  3. ^
    doi:10.1086/190662
    .
  4. ^
    S2CID 119257644
    .
  5. ^
    CDS. Retrieved September 17, 2008. ID V/50
    .
  6. doi:10.1051/0004-6361/201014840
    .
  7. ^
    doi:10.1093/mnras/stx1433
    .
  8. ^
    doi:10.1093/mnras/staa058
    .
  9. ^ "bet Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-11.
  10. ^
    S2CID 14878976
    .
  11. ^ a b "Naming Stars". IAU.org. Retrieved 2 March 2018.
  12. Bibcode:1997A&A...323L..49P
    .
  13. ISBN 978-3-642-11601-8
    .
  14. ^ a b Kaler, James B. "RASTABAN (Beta Draconis)". STARS. Retrieved 2021-01-11.
  15. doi:10.1086/323920
    . Retrieved 2015-07-22.
  16. S2CID 123149047
    .
  17. Bibcode:2005KFNT...21..141K
    .
  18. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original
    on 2012-03-18. Retrieved 2012-01-16.
  19. doi:10.1088/0004-6256/139/5/1968
    .
  20. Bibcode:1996ASPC..109..291S
    .
  21. doi:10.1086/162358
    .
  22. S2CID 118564860
    .
  23. doi:10.1086/305195
    .
  24. ^
    S2CID 54001919
    .
  25. ^
    Bibcode:1997ESASP1200.....E
    .
  26. ^ "bet Dra". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 2020-01-11.
  27. arXiv:1012.0707 [astro-ph.SR
    ].
  28. ^
    ISBN 0-486-21079-0
    . Retrieved 2010-12-12.
  29. ^
    ISBN 978-1-931559-44-7
    .
  30. ^ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. Retrieved 22 May 2016.
  31. ISBN 978-986-7332-25-7
    .
  32. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  33. ^ Wright, Anne. "Alwaid". Constellations of Words. Retrieved September 17, 2008.

External links

  • Dibon-Smith, Richard (1992). StarList 2000: A Quick Reference Star Catalog for Astronomers. New York: John Wiley & Sons.
    ISBN 0-471-55895-8
    .


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