Astronomy:Beta Canum Venaticorum

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Short description: Star in constellation Canes Venatici
β Canum Venaticorum
Location of β Canum Venaticorum (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Canes Venatici
Right ascension  12h 33m 44.54425s[1]
Declination +41° 21′ 26.9214″[1]
Apparent magnitude (V) 4.25[2]
Characteristics
Evolutionary stage main sequence[1]
Spectral type G0 V[3]
U−B color index 0.04[4]
B−V color index 0.58[4]
Astrometry
Radial velocity (Rv)+6.15±0.12[1] km/s
Proper motion (μ) RA: −704.702[1] mas/yr
Dec.: +292.155[1] mas/yr
Parallax (π)118.0266 ± 0.1530[1] mas
Distance27.63 ± 0.04 ly
(8.47 ± 0.01 pc)
Absolute magnitude (MV)4.64[5]
Details
Mass0.91+0.05
−0.07[6] M☉
Radius1.02±0.02[7] R☉
Luminosity1.254±0.009[8] L☉
Surface gravity (log g)4.41±0.04[8] cgs
Temperature6,013±91[8] K
Metallicity [Fe/H]−0.2±0.01[8] dex
Rotational velocity (v sin i)2.9±0.4[9] km/s
Age3.4[10] to 7.1[5] Gyr
Other designations
Chara, β CVn, 8 CVn, BD+42 2321, FK5 470, GJ 475, HD 109358, HIP 61317, HR 4785, SAO 44230, NGC 4530[11]
Database references
SIMBADdata
ARICNSdata

Beta Canum Venaticorum, proper name Chara, is the second-brightest star in the northern constellation of Canes Venatici. It is a nearby solar analog, located 27.6 light-years (8.5 parsecs) from the Sun based on its parallax. The star is faintly visible to the naked eye, at an apparent magnitude of +4.25. Along with the brighter star Cor Caroli, the pair form the "southern dog" in this constellation that represents hunting dogs.

Nomenclature

β Canum Venaticorum (Latinised to Beta Canum Venaticorum) is the star's Bayer designation, abbreviated Beta CVn or β CVn. It has the Flamsteed designation 8 Canum Venaticorum.[11] The star was listed in the New General Catalogue as NGC 4530.[12][13]

The traditional name Chara, pronounced /ˈkɛərə/,[14][15] was originally applied to the "southern dog", but it later became used specifically to refer to Beta Canum Venaticorum. Chara (χαρά) means 'joy' in Greek[16] but ‍‘dear’ ‍or ‍’beloved’ in Latin.[17] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[18] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[19] included a table of the first two batches of names approved by the WGSN; which included Chara for this star.

In Chinese, 常陳 (Cháng Chén), meaning Imperial Guards, refers to an asterism consisting of Beta Canum Venaticorum, Alpha Canum Venaticorum, 10 Canum Venaticorum, 6 Canum Venaticorum, 2 Canum Venaticorum, and 67 Ursae Majoris.[20] Consequently, the Chinese name for Beta Canum Venaticorum itself is 常陳四 (Cháng Chén sì, English: the Fourth Star of Imperial Guards.)[21]

Characteristics

Beta CVn has a stellar classification of G0 V, and so is a G-type main-sequence star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[22] The spectrum of this star shows a very weak emission line of singly ionized calcium (Ca II) from the chromosphere, making it a useful reference star for a reference spectrum to compare with other stars in a similar spectral category.[23] (The Ca-II emission lines are readily accessible and can be used to measure the level of activity in a star's chromosphere.)

Beta CVn is considered to be slightly metal-poor,[8] which means it has a somewhat lower portion of elements heavier than helium when compared to the Sun. In terms of mass, age and evolutionary status, however, this star is very similar to the Sun.[24] As a result, it has been called a solar analog. It is about 3% less massive than the Sun,[2] with a radius 3% larger than the Sun's and 25% greater luminosity.[25][8]

The components of this star's space velocity are (U, V, W) = (–25, 0, +2) km/s.[24] In the past it was suggested that it may be a spectroscopic binary. However, further analysis of the data does not seem to bear that out.[26] In addition, a 2005 search for a brown dwarf in orbit around this star failed to discover any such companion, at least down to the sensitivity limit of the instrument used.[27]

Habitability

In 2006, astronomer Margaret Turnbull labeled Beta CVn as the top stellar system candidate to search for extraterrestrial life forms.[28] Because of its solar-type properties, astrobiologists have listed it among the most astrobiologically interesting stars within 10 parsecs of the Sun.[24] However, as of 2009, this star is not known to host planets.[2]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 van Belle, Gerard T.; von Braun, Kaspar (April 2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal 694 (2): 1085–1098. doi:10.1088/0004-637X/694/2/1085. Bibcode: 2009ApJ...694.1085V. 
  3. ↑ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series 71: 245. doi:10.1086/191373. Bibcode: 1989ApJS...71..245K. 
  4. ↑ 4.0 4.1 Argue, A. N. (1966). "UBV photometry of 550 F, G and K type stars". Monthly Notices of the Royal Astronomical Society 133 (4): 475–493. doi:10.1093/mnras/133.4.475. Bibcode: 1966MNRAS.133..475A. 
  5. ↑ 5.0 5.1 Holmberg, J. et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics 501 (3): 941–947. doi:10.1051/0004-6361/200811191. Bibcode: 2009A&A...501..941H. 
  6. ↑ Harada, Caleb K. et al. (2024-06-01). "Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets". The Astrophysical Journal Supplement Series 272 (2): 30. doi:10.3847/1538-4365/ad3e81. ISSN 0067-0049. Bibcode: 2024ApJS..272...30H. 
  7. ↑ Baines, Ellyn K.; Clark, James H.; Kingsley, Bradley I.; Schmitt, Henrique R.; Stone, Jordan M. (2025-05-07). "Vintage NPOI: New and Updated Angular Diameters for 145 Stars" (in en). The Astronomical Journal 169 (6): 293. doi:10.3847/1538-3881/adc930. ISSN 1538-3881. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Soubiran, C. et al. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics 682: A145. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. Bibcode: 2024A&A...682A.145S. https://ui.adsabs.harvard.edu/abs/2024A&A...682A.145S.  Beta Canum Venaticorum's database entry at VizieR.
  9. ↑ Herrero, E. et al. (January 2012). "Optimizing exoplanet transit searches around low-mass stars with inclination constraints". Astronomy & Astrophysics 537: A147. doi:10.1051/0004-6361/201117809. Bibcode: 2012A&A...537A.147H. 
  10. ↑ Llorente de Andrés, F. et al. (October 2021). "The evolution of lithium in FGK dwarf stars. The lithium-rotation connection and the Li desert". Astronomy and Astrophysics 654: A137. doi:10.1051/0004-6361/202141339. ISSN 0004-6361. Bibcode: 2021A&A...654A.137L. 
  11. ↑ 11.0 11.1 "bet CVn". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=bet+CVn. 
  12. ↑ Seligman, Courtney. "New General Catalog Objects: NGC 4500 - 4549". https://cseligman.com/text/atlas/ngc45.htm#4530. 
  13. ↑ "NGC 4530". https://cdsarc.u-strasbg.fr/viz-bin/vizExec/w/.getpuz?-plus=-+&VII/239A&N%204530. 
  14. ↑ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7. 
  15. ↑ "IAU Catalog of Star Names". http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt. 
  16. ↑ Kaler, Jim. "Beta Canum Venaticorum". Stars. University of Illinois. http://www.astro.uiuc.edu/~kaler/sow/chara.html. 
  17. ↑ Ridpath, Ian. "Canes Venatici". Star Tales online edition. http://www.ianridpath.com/startales/canesvenatici.html#whirlpool. 
  18. ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/. 
  19. ↑ "Bulletin of the IAU Working Group on Star Names, No. 1". http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf. 
  20. ↑ (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.
  21. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  22. ↑ Garrison, R. F. (December 1993). "Anchor Points for the MK System of Spectral Classification". Bulletin of the American Astronomical Society 25: 1319. Bibcode: 1993AAS...183.1710G. http://www.astro.utoronto.ca/~garrison/mkstds.html. Retrieved 2012-02-04. 
  23. ↑ Herbig, G. H. (1985). "Chromospheric H-alpha emission in F8-G3 dwarfs, and its connection with the T Tauri stars". Astrophysical Journal 289 (1): 269–278. doi:10.1086/162887. Bibcode: 1985ApJ...289..269H. 
  24. ↑ 24.0 24.1 24.2 de Mello, G. P. et al. (2006). "Astrobiologically Interesting Stars Within 10 Parsecs of the Sun". Astrobiology 6 (2): 308–331. doi:10.1089/ast.2006.6.308. PMID 16689649. Bibcode: 2006AsBio...6..308P. 
  25. ↑ Baines, Ellyn K. et al. (2017). "Fundamental parameters of 87 stars from the Navy Precision Optical Interferometer". The Astronomical Journal 155 (1): 16. doi:10.3847/1538-3881/aa9d8b. Bibcode: 2018AJ....155...30B. 
  26. ↑ Morbey, C. L.; Griffin, R. F. (1987). "On the reality of certain spectroscopic orbits". Astrophysical Journal, Part 1 317: 343–352. doi:10.1086/165281. Bibcode: 1987ApJ...317..343M. 
  27. ↑ Carson, J. C. et al. (2006). "The Cornell High-Order Adaptive Optics Survey for Brown Dwarfs in Stellar Systems. I. Observations, Data Reduction, and Detection Analyses". The Astronomical Journal 130 (3): 1212–1220. doi:10.1086/432604. Bibcode: 2005AJ....130.1212C. 
  28. ↑ "Stars searched for extraterrestrials". PhysOrg.com. 2006-02-19. http://www.physorg.com/news10993.html. 



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