Pi Capricorni

Pi Capricorni
Location of π Capricorni (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 20h 27m 19.21088s[1]
Declination −18° 12′ 42.1980″[1]
Apparent magnitude (V) +5.096[2]
Characteristics
Spectral type B8 II-III[3] or B3-5 V[4]
U−B color index −0.311[2]
B−V color index +0.013[2]
Astrometry
Radial velocity (Rv)−13[5] km/s
Proper motion (μ) RA: +16.914[6] mas/yr
Dec.: −16.983[6] mas/yr
Parallax (π)4.9614 ± 0.3495 mas[6]
Distance660 ± 50 ly
(200 ± 10 pc)
Absolute magnitude (MV)−1.01[7]
Details
π Cap Aa
Mass5.9±0.1[8] M☉
Luminosity238[9] L☉
Temperature9,623[9] K
Rotational velocity (v sin i)30[10] km/s
Age43.4±7.8[8] Myr
Other designations
Okul, π Cap, 10 Cap, ADS 13860, BD−18° 5685, HD 194636, HIP 100881, HR 7814, SAO 163592, WDS J20273-1813AB[11]
Database references
SIMBADdata

Pi Capricorni, Latinized from π Capricorni, is a triple star system in the southern constellation of Capricornus. It has the traditional star name Okul[citation needed] or Oculus (meaning eye in Latin).[12] This system appears blue-white in hue and is visible to the naked eye as a 5th magnitude star.[2] It is located approximately 660 light years distant from the Sun based on parallax,[6] but is drifting closer with a radial velocity of −13 km/s.[5]

In Chinese, 牛宿 (Niú Su), meaning Ox (asterism), refers to an asterism consisting of π Capricorni, β Capricorni, α2 Capricorni, ξ2 Capricorni, ο Capricorni and ρ Capricorni.[13] Consequently, the Chinese name for π Capricorni itself is 牛宿四 (Niú Su sì, English: the Fourth Star of Ox.)[14]

The primary member, component A, is a spectroscopic binary whose two components are separated by 0.1 arcseconds. The brighter of the two, component Aa, is a blue-white B-type bright giant or main sequence star with an apparent magnitude of +5.08. It is around 43 million years old with six times the mass of the Sun.[8] The star is radiating 238 times the Sun's luminosity from its photosphere at an effective temperature of 9,623 K.[9] The third member, component B, is an eighth magnitude star at an angular separation of 3.4″ from the primary.[15]

  1. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Rakos1982 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Cowley1972 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference houk1988 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference dr2 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Abt2002 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference oculus was invoked but never defined (see the help page).
  13. ^ (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.
  14. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 13 日
  15. ^ Cite error: The named reference wds was invoked but never defined (see the help page).