# Kappa Draconis

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Star in the constellation Draco

Kappa Draconis Location of κ Draconis (circled) near the center Observation data Epoch J2000 Equinox J2000 Constellation Draco Right ascension 12h 33m 28.94206s[1] Declination +69° 47′ 17.6331″[1] Apparent magnitude (V) 3.82[2] Characteristics Spectral type B6 IIIe[3] U−B color index −0.61[2] B−V color index −0.11[2] Astrometry Radial velocity (Rv) −11.4[4] km/s Proper motion (μ) RA: −58.162[1] mas/yr Dec.: +11.802[1] mas/yr Parallax (π) 7.1387±0.3291 mas[1] Distance 460 ± 20 ly (140 ± 6 pc) Absolute magnitude (MV) −1.95 + 2.4[5] Orbit[5] Period (P) 61.5496±0.0058 d Semi-major axis (a) 0.487±0.021 au Eccentricity (e) 0 Inclination (i) 130.0±3.4° Longitude of the node (Ω) 118.0±1.3° Semi-amplitude (K1) (primary) 6.90±0.15 km/s Details κ Dra A Mass 3.65±0.48[5] M☉ Radius 5.85±0.18[5] R☉ Luminosity 1,178±151[5] L☉ Surface gravity (log g) 3.5[6] cgs Temperature 13,982±392[5] K Metallicity [Fe/H] −0.65[7] dex Rotational velocity (v sin i) 200±12[5] km/s κ Dra B Mass 0.426±0.043[5] M☉ Radius 0.69±0.07[5] R☉ Luminosity 33±17[5] L☉ Temperature 16,700±2,000[5] K Rotational velocity (v sin i) 35±10[5] km/s Other designations κ Dra, 5 Dra, BD+70°703, FK5 472, HD 109387, HIP 61281, HR 4787, SAO 7593[8] Database references SIMBAD data

**Kappa Draconis**, [Latinized](/source/Latinisation_of_names) from κ Draconis, is a [blue giant](/source/Blue_giant) [star](/source/Star) located in the northern [circumpolar constellation](/source/Circumpolar_constellation) of [Draco](/source/Draco_(constellation)). At an [apparent magnitude](/source/Apparent_magnitude) of 3.88, it is barely visible to the [naked eye](/source/Naked_eye) when artificial lighting from cities is present. Nevertheless, it is a powerful star, approximately five time as massive as the [Sun](/source/Sun). It is about 460 [light-years](/source/Light-year) away, and is 1,400 times brighter than the Sun.

The star is currently located at [declination](/source/Declination) +69° 47′ 18″ ([right ascension](/source/Right_ascension) 12h 33m 29.0s), but due to the effects of [precession](/source/Precession), Kappa Draconis was the nearest star to the [north celestial pole](/source/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](/source/Pole_star), similar to the roughly 7° variance from perfect alignment of the much brighter (magnitude 2.08) star [Kochab](/source/Beta_Ursae_Minoris), at the same time during Earth's precession.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Properties

A [light curve](/source/Light_curve) for Kappa Draconis, plotted from *[TESS](/source/Transiting_Exoplanet_Survey_Satellite)* data[9]

Kappa Draconis is a classical [Be star](/source/Be_star), displaying [Balmer emission lines](/source/Balmer_line) in its [spectrum](/source/Stellar_spectrum).[10] It is spinning rapidly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 170 km/s.[6] The star is thought to be just entering its [red giant](/source/Red_giant) phase, having exhausted the supply of [hydrogen](/source/Hydrogen) in its [core](/source/Stellar_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.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

Kappa Draconis is a single-lined [spectroscopic binary](/source/Spectroscopic_binary).[11] The main Be star is orbited by another stellar companion, on a circular orbit with a period of 61.555 days.[12] The secondary is an unusual star, a [subdwarf B star](/source/Subdwarf_B_star).[5]

The [General Catalogue of Variable Stars](/source/General_Catalogue_of_Variable_Stars) lists Kappa Draconis as a Gamma Cassiopeiae type star, a type of eruptive [irregular variable](/source/Irregular_variable) star, whose visual magnitude varies from 3.82 to 4.01.[13] However Balona and Dziembowsk classify it as a Zeta Ophiuchi star, a type of [pulsating variable](/source/Variable_star#Pulsating_variable) star, with a primary period of 10.4 hours.[14]

## Chinese name

κ Draconis in optical light

In [Chinese](/source/Chinese_astronomy), 紫微右垣 (*Zǐ Wēi Yòu Yuán*), meaning *[Right Wall of Purple Forbidden Enclosure](/source/Purple_Forbidden_enclosure)*, refers to an asterism consisting of κ Draconis, [α Draconis](/source/Alpha_Draconis), [λ Draconis](/source/Lambda_Draconis), [24 Ursae Majoris](/source/24_Ursae_Majoris), [43 Camelopardalis](/source/43_Camelopardalis), [α Camelopardalis](/source/Alpha_Camelopardalis) and [BK Camelopardalis](/source/BK_Camelopardalis).[15] Consequently, the [Chinese name](/source/Chinese_star_name) for κ Draconis itself is 紫微右垣二 (*Zǐ Wēi Yòu Yuán èr*, English: the Second Star of Right Wall of Purple Forbidden Enclosure.),[16] representing 少尉 (*Shǎowèi*), meaning *Second Chief Judge*[17]

## References

1. ^ [***a***](#cite_ref-GaiaDR2_1-0) [***b***](#cite_ref-GaiaDR2_1-1) [***c***](#cite_ref-GaiaDR2_1-2) [***d***](#cite_ref-GaiaDR2_1-3) [***e***](#cite_ref-GaiaDR2_1-4) [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. ([Gaia collaboration](/source/Data_Processing_and_Analysis_Consortium)) (August 2018). ["*Gaia* Data Release 2: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F201833051). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **616**. A1. [arXiv](/source/ArXiv_(identifier)):[1804.09365](https://arxiv.org/abs/1804.09365). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...616A...1G](https://ui.adsabs.harvard.edu/abs/2018A&A...616A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201833051](https://doi.org/10.1051%2F0004-6361%2F201833051). [Gaia DR2 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20DR2%201683102889080253312) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-aj76_1058_2-0) [***b***](#cite_ref-aj76_1058_2-1) [***c***](#cite_ref-aj76_1058_2-2) Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", *The Astronomical Journal*, **76**: 1058, [Bibcode](/source/Bibcode_(identifier)):[1971AJ.....76.1058C](https://ui.adsabs.harvard.edu/abs/1971AJ.....76.1058C), [doi](/source/Doi_(identifier)):[10.1086/111220](https://doi.org/10.1086%2F111220)

1. **[^](#cite_ref-mnras309_1_221_3-0)** Balona, L. A.; Dziembowski, W. A. (October 1999), "Excitation and visibility of high-degree modes in stars", *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **309** (1): 221–232, [Bibcode](/source/Bibcode_(identifier)):[1999MNRAS.309..221B](https://ui.adsabs.harvard.edu/abs/1999MNRAS.309..221B), [doi](/source/Doi_(identifier)):[10.1046/j.1365-8711.1999.02821.x](https://doi.org/10.1046%2Fj.1365-8711.1999.02821.x)

1. **[^](#cite_ref-gcsrv_4-0)** Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". *Carnegie Institute Washington D.C. Publication*. [Carnegie Institute of Washington D.C.](/source/Carnegie_Institute_of_Washington_D.C.) [Bibcode](/source/Bibcode_(identifier)):[1953GCRV..C......0W](https://ui.adsabs.harvard.edu/abs/1953GCRV..C......0W).

1. ^ [***a***](#cite_ref-Klement_5-0) [***b***](#cite_ref-Klement_5-1) [***c***](#cite_ref-Klement_5-2) [***d***](#cite_ref-Klement_5-3) [***e***](#cite_ref-Klement_5-4) [***f***](#cite_ref-Klement_5-5) [***g***](#cite_ref-Klement_5-6) [***h***](#cite_ref-Klement_5-7) [***i***](#cite_ref-Klement_5-8) [***j***](#cite_ref-Klement_5-9) [***k***](#cite_ref-Klement_5-10) [***l***](#cite_ref-Klement_5-11) [***m***](#cite_ref-Klement_5-12) Klement, Robert; Baade, Dietrich; Rivinius, Thomas; Gies, Douglas R.; Wang, Luqian; Labadie-Bartz, Jonathan; Dos Santos, Pedro Ticiani; Monnier, John D.; Carciofi, Alex C.; Mérand, Antoine; Anugu, Narsireddy; Schaefer, Gail H.; Bouquin, Jean-Baptiste Le; Davies, Claire L.; Ennis, Jacob; Gardner, Tyler; Kraus, Stefan; Setterholm, Benjamin R.; Labdon, Aaron (2022). ["Dynamical Masses of the Primary be Star and Secondary sdB Star in the Single-lined Binary κ Dra (B6 IIIe)"](https://doi.org/10.3847%2F1538-4357%2Fac98b8). *The Astrophysical Journal*. **940** (1): 86. [arXiv](/source/ArXiv_(identifier)):[2210.03090](https://arxiv.org/abs/2210.03090). [Bibcode](/source/Bibcode_(identifier)):[2022ApJ...940...86K](https://ui.adsabs.harvard.edu/abs/2022ApJ...940...86K). [doi](/source/Doi_(identifier)):[10.3847/1538-4357/ac98b8](https://doi.org/10.3847%2F1538-4357%2Fac98b8). [S2CID](/source/S2CID_(identifier)) [252735283](https://api.semanticscholar.org/CorpusID:252735283).

1. ^ [***a***](#cite_ref-Saad2004_6-0) [***b***](#cite_ref-Saad2004_6-1) Saad, S. M.; Kubát, J.; Koubský, P.; Harmanec, P.; Škoda, P.; Korčáková, D.; Krtička, J.; Šlechta, M.; Božić, H.; Ak, H.; Hadrava, P.; Votruba, V. (2004). ["Properties and nature of Be stars. XXIII. Long-term variations and physical properties of κ Dra"](https://doi.org/10.1051%2F0004-6361%3A20034241). *Astronomy & Astrophysics*. **419** (2): 607–621. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0401491](https://arxiv.org/abs/astro-ph/0401491). [Bibcode](/source/Bibcode_(identifier)):[2004A&A...419..607S](https://ui.adsabs.harvard.edu/abs/2004A&A...419..607S). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20034241](https://doi.org/10.1051%2F0004-6361%3A20034241). [S2CID](/source/S2CID_(identifier)) [119007669](https://api.semanticscholar.org/CorpusID:119007669).

1. **[^](#cite_ref-Anderson2012_7-0)** Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", *Astronomy Letters*, **38** (5): 331, [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971), [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A), [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015), [S2CID](/source/S2CID_(identifier)) [119257644](https://api.semanticscholar.org/CorpusID:119257644).

1. **[^](#cite_ref-SIMBAD_8-0)** ["kap Dra"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=kap+Dra). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2012-02-06.

1. **[^](#cite_ref-MAST_9-0)** ["MAST: Barbara A. Mikulski Archive for Space Telescopes"](https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html). Space Telescope Science Institute. Retrieved 8 December 2021.

1. **[^](#cite_ref-Banerjee2012_10-0)** Banerjee, Gourav; et al. (January 2021), "Optical spectroscopy of Galactic field classical Be stars", *Monthly Notices of the Royal Astronomical Society*, **500** (3): 3926–3943, [arXiv](/source/ArXiv_(identifier)):[2011.08622](https://arxiv.org/abs/2011.08622), [Bibcode](/source/Bibcode_(identifier)):[2021MNRAS.500.3926B](https://ui.adsabs.harvard.edu/abs/2021MNRAS.500.3926B), [doi](/source/Doi_(identifier)):[10.1093/mnras/staa3469](https://doi.org/10.1093%2Fmnras%2Fstaa3469).

1. **[^](#cite_ref-Hutter_11-0)** Hutter, D. J.; Tycner, C.; Zavala, R. T.; Benson, J. A.; Hummel, C. A.; Zirm, H. (2021). ["Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars"](https://doi.org/10.3847%2F1538-4365%2Fac23cb). *The Astrophysical Journal Supplement Series*. **257** (2): 69. [arXiv](/source/ArXiv_(identifier)):[2109.06839](https://arxiv.org/abs/2109.06839). [Bibcode](/source/Bibcode_(identifier)):[2021ApJS..257...69H](https://ui.adsabs.harvard.edu/abs/2021ApJS..257...69H). [doi](/source/Doi_(identifier)):[10.3847/1538-4365/ac23cb](https://doi.org/10.3847%2F1538-4365%2Fac23cb). [S2CID](/source/S2CID_(identifier)) [237503492](https://api.semanticscholar.org/CorpusID:237503492).

1. **[^](#cite_ref-Saad2005_12-0)** Saad, S. M.; Kubát, J.; Hadrava, P.; Harmanec, P.; Koubský, P.; Škoda, P.; Šlechta, M.; Korčáková, D.; Yang, S. (2005). "Spectrum Disentangling and Orbital Solution for κ Dra". *Astrophysics and Space Science*. **296** (1–4): 173–177. [Bibcode](/source/Bibcode_(identifier)):[2005Ap&SS.296..173S](https://ui.adsabs.harvard.edu/abs/2005Ap&SS.296..173S). [doi](/source/Doi_(identifier)):[10.1007/s10509-005-4438-7](https://doi.org/10.1007%2Fs10509-005-4438-7). [S2CID](/source/S2CID_(identifier)) [189844885](https://api.semanticscholar.org/CorpusID:189844885).

1. **[^](#cite_ref-gcvs_13-0)** ["Query= kap Dra"](http://www.sai.msu.su/gcvs/cgi-bin/search2.cgi?search=kap+Dra). *General Catalog of Variable Stars*. Sternberg Astronomical Institute. Retrieved 19 December 2022.

1. **[^](#cite_ref-Balona_14-0)** Balona, L. A.; Dziembowski, W. A. (October 1999). ["Excitation and visibility of high-degree modes in stars"](https://doi.org/10.1046%2Fj.1365-8711.1999.02821.x). *Monthly Notices of the Royal Astronomical Society*. **309** (1): 221–232. [Bibcode](/source/Bibcode_(identifier)):[1999MNRAS.309..221B](https://ui.adsabs.harvard.edu/abs/1999MNRAS.309..221B). [doi](/source/Doi_(identifier)):[10.1046/j.1365-8711.1999.02821.x](https://doi.org/10.1046%2Fj.1365-8711.1999.02821.x).

1. **[^](#cite_ref-zh_15-0)** (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](/source/ISBN_(identifier)) [978-986-7332-25-7](https://en.wikipedia.org/wiki/Special:BookSources/978-986-7332-25-7).

1. **[^](#cite_ref-aeea_16-0)** (in Chinese) [AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 11 日](http://aeea.nmns.edu.tw/2006/0606/ap060611.html) [Archived](https://web.archive.org/web/20110522121054/http://aeea.nmns.edu.tw/2006/0606/ap060611.html) 2011-05-22 at the [Wayback Machine](/source/Wayback_Machine)

1. **[^](#cite_ref-lcsd_17-0)** [English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name](http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#PrupleForbiddenEnclosure) [Archived](https://web.archive.org/web/20080924022136/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm) 2008-09-24 at the [Wayback Machine](/source/Wayback_Machine), Hong Kong Space Museum. Accessed on line November 23, 2010.

## External links

- [Kappa Draconis](https://web.archive.org/web/20061011012648/http://www.astro.uiuc.edu/%7Ekaler/sow/kappadra.html) by Jim Kaler

v t e Constellation of Draco List of stars in Draco Draco in Chinese astronomy Stars Bayer α (Thuban) β (Rastaban) γ (Eltanin) δ (Altais) ε (Tyl) ζ (Aldhibah) η (Athebyne) θ ι (Edasich) κ λ (Giausar) μ (Alrakis) ν (Kuma) ξ (Grumium) ο π ρ σ (Alsafi) τ υ φ χ ψ1 (Dziban) ψ2 ω Flamsteed 4 6 7 (Tianyi) 8 (Taiyi) 10 (i) 15 (A) 18 (g) 19 (h) 26 36 39 (b) 42 (Fafnir) 45 (d) 50 59 64 (e) 68 Variable TW YY AG BY CL CM CX DO EK HP V581 HR 3751 4126 4934 5811 6237 6518 6618 (Alruba) 6817 7137 7783 HD 109246 (Funi) 101364 128717 147379 156279 158259 176693 191939 Other 2MASS 1237+6526 2MASS J17554042+6551277 G 240-72 GD 356 Gliese 420 Gliese 625 Gliese 687 GRW +70 8247 Kepler-4 Kepler-10 Kepler-12 Kepler-90 Kepler-296 KOI-256 LP 71-82 Qatar-1 SDSS J1240+6710 Struve 2398 TOI-1136 WD 1856+534 WISE 1647+5632 WISE 1841+7000 Exoplanets HD 139357 b HD 167042 b ι Dra b (Hypatia) Kepler-4b Kepler-10b c Kepler-12b Kepler-90e f g h i Kepler-296b c d e f TOI-1452 b TrES-2b Star clusters LAMOST 1 Nebulae Cat's Eye Nebula NGC 6742 Galaxies NGC 3147 3197 3735 4121 4125 4221 4236 4319 4331 4332 4363 4441 4513 4545 4589 5678 5777 5866 5866B 5879 5905 5907 5949 5963 5965 5982 5985 6090 6248 6285 6286 6338 6340 6365 6373 6394 6412 6503 6505 6566 6621 6622 6670 6676 6786 6789 Other 1ES 1927+654 1ES 1959+650 3C 249.1 3C 305 3C 319 3C 343 3C 343.1 3C 351 3C 356 3C 371 3C 380 3C 390.3 3C 401 4C +72.26 4C 73.08 8C 1241+735 Abell 2218 BCG Bean galaxy Beaver galaxy BZQ J1727+5510 Draco Dwarf Draco II GB 1508+5714 Goldfish galaxy H1821+643 HFLS3 IERS B1946+708 IRAS F17179+5444 IRAS 18580+6527 J120011.1+680924.8 KKR 25 Markarian 817 Markarian 876 Original TRG PGC 39058 Porphyrion QSO B1823+568 RGZ J172749.5+534647 S5 1803+784 S5 2007+777 SDSS J1715+6008 Tadpole Galaxy UGC 9391 UGC 9405 UGC 11241 UGC 11411 WISEA J145223.62+611707.5 WN B1851+5707 Galaxy clusters Abell 2218 CL1358+62 Draco Supercluster NGC 5866 Group Astronomical events SN 2003jb SN 2005B SN 2016aps Swift J1644+57 Category

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Adapted from the Wikipedia article [Kappa Draconis](https://en.wikipedia.org/wiki/Kappa_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Kappa_Draconis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.