Astronomy:Chi Ursae Majoris

From HandWiki
Short description: Star in the constellation Ursa Major
Chi Ursae Majoris
Location of χ Ursae Majoris (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ursa Major
Right ascension  11h 46m 03.01407s[1]
Declination +47° 46′ 45.8553″[1]
Apparent magnitude (V) 3.72[2]
Characteristics
Evolutionary stage Horizontal branch[3]
Spectral type K0.5 IIIb[4]
U−B color index +1.16[2]
B−V color index +1.18[2]
Astrometry
Radial velocity (Rv)−9.02±0.20[2] km/s
Proper motion (μ) RA: −138.297[1] mas/yr
Dec.: +28.66[1] mas/yr
Parallax (π)16.438 ± 0.113[1] mas
Distance198 ± 1 ly
(60.8 ± 0.4 pc)
Absolute magnitude (MV)0.10±0.02[5]
Details[2]
Mass1.49[6] M☉
Radius23.15±0.21[7] R☉
Luminosity170.1±5.3[7] L☉
Surface gravity (log g)2.2 cgs
Temperature4,331±33[7] K
Metallicity [Fe/H]−0.44 dex
Rotational velocity (v sin i)2.3 km/s
Other designations
Taiyangshou, Alkaphrah[8], Alkafzah[8], Chi UMa, χ UMa, 63 Ursae Majoris, BD+48°1966, FK5 441, HD 102224, HIP 57399, HR 4518, SAO 43886[9]
Database references
SIMBADdata

Chi Ursae Majoris or χ Ursae Majoris, formally named Taiyangshou /ˌtaɪˌjæŋˈʃoʊ/,[10] is a single[11] star in the northern circumpolar constellation of Ursa Major. The star has an orange hue and is visible to the naked eye at night with an apparent visual magnitude of 3.72.[2] It is located at a distance of approximately 198 light-years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −9 km/s.[2]

Nomenclature

Chi Ursae Majoris and NGC 3877

χ Ursae Majoris (Latinised to Chi Ursae Majoris) is the star's Bayer designation.

It bore the traditional name Taiyangshou (太陽守, Pinyin: Tàiyángshǒu), meaning Guard of the Sun, from Chinese astronomy.[12] It is a single-star asterism in the Purple Forbidden enclosure (see: Chinese constellations). In R. H. Allen's Star Names, this name was transliterated as Tai Yang Show, "the Sun Governor".[13] The star has also been called Alkafzah, Al Kaphrah, or El Kophrah,[8][13] from Arabic القفزة al-qafzah "the leap [of the gazelle]", which refers to an asterism consisting of ι, κ, λ, μ, ν, and ξ Ursae Majoris.[12]

In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN approved the name Taiyangshou for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names. The name Alkaphrah was approved for κ Ursae Majoris.[10]

Properties

Chi Ursae Majoris is an evolved, orange hued K-type giant with a stellar classification of K0.5 IIIb.[4] It is a red clump giant,[3] which means it is on the horizontal branch and is generating energy through helium fusion at its core. This star has expanded to 23[7] times the radius of the Sun with 1.49 times the Sun's mass.[6] It is radiating 170 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,331 K.[7]

The spiral galaxy in Ursa Major, NGC 3877 (= H I.201), type Sc, is best found from Chi Ursae Majoris, which is almost exactly 15 arcminutes north of the galaxy.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 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 2.3 2.4 2.5 2.6 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society 172 (3): 667–679, doi:10.1093/mnras/172.3.667, Bibcode: 1975MNRAS.172..667J. 
  3. ↑ 3.0 3.1 Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, doi:10.1086/309278, Bibcode: 2000ApJ...539..732A. 
  4. ↑ 4.0 4.1 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. 
  5. ↑ Park, Sunkyung et al. (2013), "Wilson-Bappu Effect: Extended to Surface Gravity", The Astronomical Journal 146 (4): 73, doi:10.1088/0004-6256/146/4/73, Bibcode: 2013AJ....146...73P. 
  6. ↑ 6.0 6.1 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Baines, Ellyn K.; Thomas Armstrong, J.; Clark, James H.; Gorney, Jim; Hutter, Donald J.; Jorgensen, Anders M.; Kyte, Casey; Mozurkewich, David et al. (2021). "Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer". The Astronomical Journal 162 (5): 198. doi:10.3847/1538-3881/ac2431. Bibcode: 2021AJ....162..198B. 
  8. ↑ 8.0 8.1 8.2 Bakich, Michael E. (1995), The Cambridge Guide to the Constellations, Cambridge University Press, pp. 112, 116, ISBN 0521449219, https://books.google.com/books?id=tLMXiFhTnRYC&pg=PA112 
  9. ↑ "chi UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=chi+UMa. 
  10. ↑ 10.0 10.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/. Retrieved 16 December 2017. 
  11. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E. 
  12. ↑ 12.0 12.1 Ridpath, Ian. "Star Tales – Ursa Major 2". http://www.ianridpath.com/startales/ursamajor2.html. 
  13. ↑ 13.0 13.1 Allen, R. H. (1899). Star Names: Their Lore and Meaning. pp. 444-445. https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Ursa_Major*.html. 
  14. ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/. Retrieved 22 May 2016. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:Chi_Ursae_Majoris&oldid=4213504"