Kappa Scorpii

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Star in the constellation Scorpius

title: "Kappa Scorpii" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["scorpius", "bayer-objects", "b-type-giants", "spectroscopic-binaries", "beta-cephei-variables", "stars-with-proper-names", "hipparcos-objects", "bright-star-catalogue-objects", "henry-draper-catalogue-objects", "durchmusterung-objects"] description: "Star in the constellation Scorpius" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Kappa_Scorpii" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Scorpius ::

| name=κ Scorpii | image= |image=Scorpius constellation map.svg |float=center |alt= |label= |position=right |width=260 |mark=Red circle.svg |mark_width=12 |mark_link=κ Scorpii |x=202|y=770 |caption=Location of κ Sco (circled) | epoch = J2000 | ra = | dec = | appmag_v = 2.41 - 2.42 | constell = Scorpius | class = B1.5 III | b-v = −0.228 | u-b = −0.914 | variable = β Cephei | radial_v = −14.0 | prop_mo_ra = −6.05 | prop_mo_dec = −25.54 | parallax = 6.75 | p_error = 0.17 | parallax_footnote = | absmag_v = | reference = | period_unitless = days | axis_unitless = mas | eccentricity = | inclination = | node = | periarg = | periastron = | k1 = | source = | component1 = κ Sco A | mass = | radius = | temperature = 23,170 | metal_fe = | rotation = days | rotational_velocity = 105 | gravity = | age_myr = | component2 = κ Sco B | mass2 = | radius2 = 5.8 | temperature2 = 22,750 | gravity2 = 3.92 | age_myr2 = | names = |Simbad=kap+Sco

Kappa Scorpii, Latinized from κ Scorpii, is a binary star system in the southern constellation of Scorpius. With an apparent visual magnitude of 2.4, this star system is readily visible to the naked eye. Parallax measurements place it at an estimated distance of roughly 480 ly from the Earth.

Nomenclature

κ Scorpii has been called Girtab , which is the Sumerian word for 'scorpion'. The name has survived through the Babylonian star catalogues, and was originally applied to an asterism comprising this star, λ Scorpii, υ Scorpii, and ι Scorpii. Other sources have used the name Girtab for θ Scorpii (Sargas) or ι1 Scorpii. The latter appeared in a 1971 NASA catalog of star names that listed κ Scorpii as Mula, after an Indian asterism (nakshatra) in the same region.

In Chinese, 尾宿 (Wěi Xiù), meaning Tail, refers to an asterism consisting κ Scorpii, μ1 Scorpii, ε Scorpii, ζ1 Scorpii and ζ2 Scorpii, η Scorpii, θ Scorpii, ι1 Scorpii and ι2 Scorpii, λ Scorpii and υ Scorpii. Consequently, the Chinese name for κ Scorpii itself is 尾宿七 (Wěi Xiù qī), "the Seventh Star of Tail".

The Kamilaroi and Euahlayi Aboriginal peoples of New South Wales, Australia call this star Gidjirrigaa, the budgerigar.

Properties

This is a spectroscopic binary, which is a type of binary star system in which the two stars are so close together that they have not been individually resolved with a telescope. The pair orbit each other with a period of about 195 days and an eccentricity of about 0.5. The combined spectrum of this pair matches a star with a stellar classification of B1.5 III. The 'III' luminosity class indicates the presence of a giant star that has exhausted the supply of hydrogen at its core and is in a late evolutionary stage.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/cb/KappaScoLightCurve.png" caption="A [[light curve]] for Kappa Scorpii, adapted from Lomb and Shobbrook (1975)"] ::

The primary component of the pair, κ Sco A, is a variable star of Beta Cephei type. It is undergoing radial pulsations with a dominant frequency of five cycles per day, or 4.8 hours per cycle. There are overlapping secondary pulsation frequencies of about 4.85 and 5.69 cycles per day. This star has about 11 times the mass of the Sun and is nearly 7 times the Sun's radius. The effective temperature of the outer envelope is 23,400 K, giving it a blue-white hue. It is rotating rapidly, with an estimated period of only 1.9 days and an axis of rotation that is inclined by about 40° to the line of sight from the Earth.

The secondary component, κ Sco B, is smaller than the primary, but still much larger than the Sun. It has about 10 times the mass of the Sun and nearly six times the Sun's radius. The effective temperature of 18,800 K is also higher than the Sun's, which is at 5,778 K.

Cultural significance

κ Scorpii appears on the flag of Brazil, symbolising the state of Paraíba.

Notes

References

References

  1. from "Fixed Period Only" model
  2. (2013). "Time-resolved multicolour photometry of bright B-type variable stars in Scorpius". Astronomy & Astrophysics.
  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. {{in lang. zh [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive. link. (2008-10-25 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
  5. (1978). "Michigan catalogue of two-dimensional spectral types for the HD star". Dept. of Astronomy, University of Michigan: distributed by University Microfilms International.
  6. (1999). "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions". Astronomisches Rechen-Institut Heidelberg.
  7. (June 1968). "A photometric investigation of the Scorpio-Centaurus association".
  8. (1970). "A Catalogue of Stellar Rotational Velocities". Contributi Osservatorio Astronomico di Padova in Asiago.
  9. (12 September 2012). "Science and technology progress at the Sydney University Stellar Interferometer". Proceedings of the SPIE.
  10. (March 2005). "Disentangling component spectra of κ Scorpii, a spectroscopic binary with a pulsating primary. II. Interpretation of the line-profile variability". Astronomy and Astrophysics.
  11. (June 2001). "Line-profile variations of the double-lined spectroscopic binary kappa Scorpii". Astronomy and Astrophysics.
  12. (2011). "The Mythology of the Night Sky: An Amateur Astronomer's Guide to the Ancient Greek and Roman Legends". Springer.
  13. (1989). "Star tales". James Clarke & Co..
  14. "Girtab". University of Illinois.
  15. "IAU Catalog of Star Names".
  16. "Kamilaroi and Euahlayi – Australian Indigenous Astronomy".

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scorpiusbayer-objectsb-type-giantsspectroscopic-binariesbeta-cephei-variablesstars-with-proper-nameshipparcos-objectsbright-star-catalogue-objectshenry-draper-catalogue-objectsdurchmusterung-objects