Astronomy:Psi Capricorni

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Short description: Star in the constellation Capricornus
Psi Capricorni
Capricornus constellation map.svg
Red circle.svg
Location of ψ Capricorni (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Capricornus
Right ascension  20h 46m 05.73263s[1]
Declination −25° 16′ 15.2312″[1]
Apparent magnitude (V) 4.13[2]
Characteristics
Spectral type F5 V[3]
U−B color index −0.03[2]
B−V color index +0.42[2]
Astrometry
Radial velocity (Rv)+20.3[4] km/s
Proper motion (μ) RA: −51.96[1] mas/yr
Dec.: −156.56[1] mas/yr
Parallax (π)68.13 ± 0.27[1] mas
Distance47.9 ± 0.2 ly
(14.68 ± 0.06 pc)
Absolute magnitude (MV)3.33[5]
Details
Mass1.37[6] M
Radius1.51+0.08
−0.04
[7] R
Luminosity3.82±0.03[7] L
Surface gravity (log g)4.25[6] cgs
Temperature6,572+89
−173
[7] K
Metallicity [Fe/H]0.15[6] dex
Rotational velocity (v sin i)40.9±2.0[8] km/s
Age1.4[3] Gyr
Other designations
ψ Cap, 16 Capricorni, CD−25°15018, FK5 779, GC 805, HD 197692, HIP 102485, HR 7936, SAO 189664[9]
Database references
SIMBADdata

Psi Capricorni, Latinized from ψ Capricorni, is a single[10] star in the southern zodiac constellation of Capricornus. It is a yellow-white hued star that is faintly visible to the naked eye with an apparent visual magnitude of +4.13.[2] The distance to this star is approximately 47.9 light years based on parallax measurements,[1] and it is drifting further away with a radial velocity of +20 km/s.[4] The closest approach to the Sun occurred some 467,000 years ago at a separation of 20 light-years.[11]

This object is an F-type main-sequence star with a stellar classification of F5 V/[3] It is 1.4[3] billion years old with 1.4[6] times the mass of the Sun. The measured rotational velocity of this star is approximately 41 km/s[8] (the Sun has an equatorial rotation velocity of 2 km/s). Analysis of the line profile of the star's spectrum indicates that it is undergoing differential rotation, with the variation by latitude being similar to the Sun.[12] The star has 1.5[7] times the Sun's radius and is radiating 3.8[7] times the luminosity of the Sun from its photosphere at an effective temperature of 6,572 K.[7] It displays an infrared excess, suggesting the presence of an orbiting debris disk at a separation of 38.75 astronomical unit|AU and a temperature of 60 K.[13]

Chinese name

In Chinese, 天田 (Tiān Tián), meaning Celestial Farmland, refers to an asterism consisting of ψ Capricorni, ω Capricorni, 3 Piscis Austrini, and 24 Capricorni.[14] Consequently, the Chinese name for ω Capricorni itself is 天田四 (Tiān Tián sì, English: the Fourth Star of Celestial Farmland).[15]

In R. H. Allen's version, this star represented the battle-axe Yue.[16]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 3.2 3.3 Ehrenreich, D. et al. (November 2010), "Deep infrared imaging of close companions to austral A- and F-type stars", Astronomy and Astrophysics 523: A73, doi:10.1051/0004-6361/201014763, Bibcode2010A&A...523A..73E. 
  4. 4.0 4.1 Nordström, B. et al. (2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14000 F and G dwarfs", Publications of the Astronomical Society of Australia 21 (2): 129–133, doi:10.1071/AS04013, Bibcode2004PASA...21..129N. 
  5. Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics 446 (1): 267–277, doi:10.1051/0004-6361:20053911, Bibcode2006A&A...446..267R 
  6. 6.0 6.1 6.2 6.3 Luck, R. Earle (March 2018), "Abundances in the Local Region. III. Southern F, G, and K Dwarfs", The Astronomical Journal 155 (3): 31, doi:10.3847/1538-3881/aaa9b5, 111, Bibcode2018AJ....155..111L. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  8. 8.0 8.1 Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics 542: A116, doi:10.1051/0004-6361/201118724, Bibcode2012A&A...542A.116A. 
  9. "psi Cap". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=psi+Cap. 
  10. 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, Bibcode2008MNRAS.389..869E. 
  11. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, doi:10.1051/0004-6361/201425221, A35, Bibcode2015A&A...575A..35B. 
  12. Reiners, Ansgar; Schmitt, Jürgen H. M. M.; Kürster, Martin (September 2001), "Detection of differential rotation in psi Cap with profile analysis", Astronomy and Astrophysics 376: L13–L16, doi:10.1051/0004-6361:20011023, Bibcode2001A&A...376L..13R. 
  13. Gáspár, András et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal 826 (2): 171, doi:10.3847/0004-637X/826/2/171, Bibcode2016ApJ...826..171G. 
  14. (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.
  15. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日
  16. Allen, R. H. (1963), Star Names, Dover, p. 142, https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Capricornus*.html 

External links