Kappa Draconis

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Star in the constellation Draco

title: "Kappa Draconis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["b-type-giants", "be-stars", "spectroscopic-binaries", "draco-(constellation)", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects", "northern-pole-stars", "b-type-subdwarfs"] description: "Star in the constellation Draco" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Kappa_Draconis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Draco ::

| image = | image=Draco IAU.svg | float=center | width=240 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=ι Exa | x%=68.9 | y%=29.9 | caption=Location of κ Draconis (circled) near the center | epoch = J2000 | ra = | dec = | appmag_v = 3.82 | constell = Draco | type = | class = B6 IIIe | b-v = −0.11 | u-b = −0.61 | r-i = | variable = | radial_v = −11.4 | prop_mo_ra = −58.162 | prop_mo_dec = +11.802 | parallax = 7.1387 | p_error = 0.3291 | parallax_footnote = | absmag_v = −1.95 + 2.4 | reference = | period_unitless = 61.5496 ± 0.0058 d | eccentricity = 0 | k1 = 6.90±0.15 | inclination = 130.0 ± 3.4 | node = 118.0 ± 1.3 | axis_unitless = 0.487 ± 0.021 au | component1 = κ Dra A | mass = 3.65 ± 0.48 | temperature = 13982 ± 392 | radius = 5.85 ± 0.18 | luminosity = 1178 ± 151 | metal_fe = −0.65 | gravity = 3.5 | rotational_velocity = 200 ± 12 | age_gyr = | component2 = κ Dra B | mass2 = 0.426 ± 0.043 | temperature2 = 16700 ± 2000 | radius2 = 0.69 ± 0.07 | luminosity2 = 33 ± 17 | rotational_velocity2 = 35 ± 10 | names = | Simbad = kap+Dra

Kappa Draconis, Latinized from κ Draconis, is a blue giant star located in the northern circumpolar constellation of Draco. At an apparent magnitude of 3.88, it is barely visible to the naked eye when artificial lighting from cities is present. Nevertheless, it is a powerful star, approximately five time as massive as the Sun. It is about 460 light-years away, and is 1,400 times brighter than the Sun.

The star is currently located at declination (right ascension ), but due to the effects of precession, Kappa Draconis was the nearest star to the north celestial pole visible to the naked eye from 1793 BC to approximately 1000 BC, though it was 6° removed from perfect alignment, making it only an approximate pole star, similar to the roughly 7° variance from perfect alignment of the much brighter (magnitude 2.08) star Kochab, at the same time during Earth's precession.

Properties

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b6/KappaDraLightCurve.png" caption="TESS]]'' data"] ::

Kappa Draconis is a classical Be star, displaying Balmer emission lines in its spectrum. It is spinning rapidly with a projected rotational velocity of 170 km/s. The star is thought to be just entering its red giant phase, having exhausted the supply of hydrogen in its core. Over the next several thousand years, the star will expand, becoming more powerful but with a much cooler surface temperature. Tens of thousands of years from now, Kappa Draconis will appear much brighter, probably shining with a reddish hue.

Kappa Draconis is a single-lined spectroscopic binary. The main Be star is orbited by another stellar companion, on a circular orbit with a period of 61.555 days. The General Catalogue of Variable Stars lists Kappa Draconis as a Gamma Cassiopeiae type star, a type of eruptive irregular variable star, whose visual magnitude varies from 3.82 to 4.01. However Balona and Dziembowsk classify it as a Zeta Ophiuchi star, a type of pulsating variable star, with a primary period of 10.4 hours.

Chinese name

::figure[src="https://upload.wikimedia.org/wikipedia/commons/1/16/Kappa_Draconis.jpg" caption="κ Draconis in optical light"] ::

In Chinese, 紫微右垣 (Zǐ Wēi Yòu Yuán), meaning Right Wall of Purple Forbidden Enclosure, refers to an asterism consisting of κ Draconis, α Draconis, λ Draconis, 24 Ursae Majoris, 43 Camelopardalis, α Camelopardalis and BK Camelopardalis. Consequently, the Chinese name for κ Draconis itself is 紫微右垣二 (Zǐ Wēi Yòu Yuán èr, .), representing 少尉 (Shǎowèi), meaning Second Chief Judge

References

| title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

| title=Optical spectroscopy of Galactic field classical Be stars | last1=Banerjee | first1=Gourav | last2=Mathew | first2=Blesson | last3=Paul | first3=K. T. | last4=Subramaniam | first4=Annapurni | last5=Bhattacharyya | first5=Suman | last6=Anusha | first6=R. | display-authors=1 | postscript=. | journal=Monthly Notices of the Royal Astronomical Society | volume=500 | issue=3 | pages=3926–3943 | date=January 2021 | doi=10.1093/mnras/staa3469 | doi-access=free | arxiv=2011.08622 | bibcode=2021MNRAS.500.3926B }}

References

  1. [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#PrupleForbiddenEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive. link. (2008-09-24 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
  2. {{in lang. zh [http://aeea.nmns.edu.tw/2006/0606/ap060611.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 11 日] {{Webarchive. link. (2011-05-22)
  3. {{in lang. zh ''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.
  4. {{Cite Gaia DR2. 1683102889080253312
  5. (2005). "Spectrum Disentangling and Orbital Solution for κ Dra". Astrophysics and Space Science.
  6. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute.
  7. "Query= kap Dra". Sternberg Astronomical Institute.
  8. (October 1999). "Excitation and visibility of high-degree modes in stars". Monthly Notices of the Royal Astronomical Society.
  9. Wilson, R. E.. (1953). "General Catalogue of Stellar Radial Velocities". [[Carnegie Institute of Washington D.C.]].
  10. (1971). "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere". The Astronomical Journal.
  11. (October 1999). "Excitation and visibility of high-degree modes in stars". [[Monthly Notices of the Royal Astronomical Society]].
  12. (2004). "Properties and nature of Be stars. XXIII. Long-term variations and physical properties of κ Dra". Astronomy & Astrophysics.
  13. (2021). "Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars". The Astrophysical Journal Supplement Series.
  14. "kap Dra".
  15. (2022). "Dynamical Masses of the Primary be Star and Secondary sdB Star in the Single-lined Binary κ Dra (B6 IIIe)". The Astrophysical Journal.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

b-type-giantsbe-starsspectroscopic-binariesdraco-(constellation)bayer-objectsdurchmusterung-objectsflamsteed-objectshenry-draper-catalogue-objectshipparcos-objectsbright-star-catalogue-objectsnorthern-pole-starsb-type-subdwarfs