Cor Caroli

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α Canum Venaticorum
The location of α Canum Venaticorum (circled)
Observation data
ICRS
)
Constellation Canes Venatici
α2 CVn
Right ascension 12h 56m 01.66622s[1]
Declination +38° 19′ 06.1541″[1]
Apparent magnitude (V) 2.84 to 2.98[2]
α1 CVn
Right ascension 12h 56m 00.43258s[1]
Declination +38° 18′ 53.3768″[1]
Apparent magnitude (V) 5.60[3]
Characteristics
α2 CVn
Spectral type A0pSiEuHg[4]
U−B color index −0.32[5]
B−V color index −0.12[5]
Variable type α2 CVn
α1 CVn
Spectral type F2V[6]
U−B color index −0.03[7]
B−V color index +0.34[7]
Distance
106.5 ± 0.2 ly
(32.67 ± 0.07 pc)
Details
α2 CVn
Rotational velocity (v sin i)
18[14] km/s
HR 4914, SAO 63256[16]
Database references
SIMBADα2 CVn
α1 CVn

Cor Caroli /ˌkɔːr ˈkærəlaɪ/ is a binary star designated Alpha Canum Venaticorum or α Canum Venaticorum. The International Astronomical Union uses the name "Cor Caroli" specifically for the brighter star of the binary.[17] Alpha Canum Venaticorum is the brightest point of light in the northern constellation of Canes Venatici.

Nomenclature

α Canum Venaticorum, Latinised to Alpha Canum Venaticorum, is the system's Bayer designation. The brighter of the two stars is designated α2 Canum Venaticorum, the fainter α1 Canum Venaticorum.[18]

In the western world Alpha Canum Venaticorum had no name until the 17th century, when it was named Cor Caroli, which means "Charles's Heart". There has been some uncertainty whether it was named in honour of King Charles I of England, who was executed in 1649 during the English Civil War, or of his son, Charles II, who restored the English monarchy to the throne in 1660. The name was coined in 1660 by Sir Charles Scarborough, physician to Charles II, who claimed the star seemed to shine exceptionally brightly on the night of Charles II's return to England. In Star Names, R.H. Allen claimed that Scarborough suggested the name to Edmond Halley and intended it to refer to Charles II.[19] However, Robert Burnham Jr. notes that "the attribution of the name to Halley appears in a report published by J. E. Bode at Berlin in 1801, but seems to have no other verification".[20] In Star Tales, Ian Ridpath points out that the name's first appearance on a star map was in the 1673 chart of Francis Lamb, who labelled it Cor Caroli Regis Martyris ('the heart of Charles the martyred king'), clearly indicating that it was seen as referring to Charles I.[21]

In 2016, the

Working Group on Star Names (WGSN)[22] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[23]
included a table of the first two batches of names approved by the WGSN; which included Cor Caroli for the star α2 Canum Venaticorum.

In

Chinese name for Alpha Canum Venaticorum itself is 常陳一 (Cháng Chén yī, English: the First Star of Imperial Guards).[25] From this Chinese name, the name Chang Chen was derived.[26]

Stellar properties

Cor Caroli seen from northern England on March 1, 2011

Alpha Canum Venaticorum is a

arcseconds apart in the sky and are easily resolved in small telescopes. The system lies approximately 110 light-years from the Sun
.

It marks the northern vertex of the asterism known as the Great Diamond or the Diamond of Virgo.

α2 Canum Venaticorum

A light curve for α2 Canum Venaticorum, plotted from TESS data[27]

α2 Canum Venaticorum has a

Ap/Bp star.[28] Its atmosphere has overabundances of some elements, such as silicon, mercury and europium. This is thought to be due to some elements sinking down into the star under the force of gravity while others are elevated by radiation pressure.[18][28] This star is the prototype of a class of variable stars, the so-called α2 Canum Venaticorum variables. The strong magnetic field of these stars is believed to produce starspots
of enormous extent. Due to these starspots the brightness of α2 Canum Venaticorum stars varies considerably during their rotation.

α1 Canum Venaticorum

α1 Canum Venaticorum is an F-type main-sequence star. It is considerably fainter than its companion and has an apparent visual magnitude of approximately 5.60.[3]

Namesakes

U.S. Navy Crater-class cargo ship
named after the star.

References

  1. ^
    S2CID 18759600
    .
  2. ^ a b alf 2 CVn, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line November 2, 2009.
  3. ^
    Bibcode:2002yCat.2237....0D
    .
  4. ^ HR 4915, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr.,
    CDS ID V/50
    . Accessed on line November 2, 2009.
  5. ^
    Bibcode:1986EgUBV........0M
    .
  6. S2CID 119417105
    .
  7. ^
    Bibcode:1966CoLPL...4...99J
    .
  8. S2CID 119231169
    .
  9. doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR
    .
  10. ^
    S2CID 53998003
    .
  11. S2CID 119054949
    .
  12. doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR
    .
  13. ^
    Bibcode:1999A&A...352..555A
    .
  14. S2CID 18475298
    .
  15. ^ a b "* alf02 CVn". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 May 2017.
  16. ^ "* alf01 CVn". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 May 2017.
  17. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  18. ^ a b Cor Caroli Archived 2008-07-04 at the Wayback Machine, Stars, Jim Kaler. Accessed on line September 15, 2008.
  19. ^ R.H. Allen, Star Names: Their Lore and Meaning.
  20. ^ Robert Burnham, Jr. Burnham's Celestial Handbook, Volume 1, p. 359.
  21. ^ Ian Ridpath: "Star Tales", Canes Venatici. See also Deborah J. Warner, The Sky Explored: Celestial Cartography 1500-1800.
  22. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  23. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  24. ^ (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 978-986-7332-25-7
    .
  25. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived September 29, 2009, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  26. ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Canes Venatici
  27. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  28. ^
    ISBN 0-387-95436-8
    .
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