Rho Capricorni

From Wikipedia, the free encyclopedia
Jump to: navigation, search
ρ Capricorni
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Capricornus
Right ascension 20h 28m 51.6s
Declination –17° 48′ 49″
Apparent magnitude (V) +4.78[1]
Distance 98.7 ± 2.6 ly
(30.3 ± 0.8 pc)
Spectral type F2 IV[1]
Other designations
11 Capricorni, ADS 13887, BD−18°5689, CCDM J20289-1750, Gl 791.1, HD 194943, HIP 101027, HR 7822, SAO 163614

Rho Capricorni (ρ Cap, ρ Capricorni) is a binary star in the constellation Capricornus. It is approximately 98.7 light years from Earth. Sometimes, this star is called by the name Bos, meaning the cow in Latin.[2]

In Chinese, 牛宿 (Niú Su), meaning Ox (asterism), refers to an asterism consisting of β Capricorni, α2 Capricorni, ξ2 Capricorni, π Capricorni, ο Capricorni and ρ Capricorni.[3] Consequently, ρ Capricorni itself is known as 牛宿六 (Niú Su liù, English: the Sixth Star of Ox.)[4]

The primary component, ρ Capricorni A, is a yellow-white F-type subgiant with an apparent magnitude of +4.77. This star has 1.5 times the mass of the Sun and 1.3 times the Sun's radius. It is radiating 3.3 as much luminosity of the Sun from its outer atmosphere at an effective temperature of 6,840 K.[1] The companion, ρ Capricorni B is an eighth magnitude star located 1.013 arcseconds, or at least 30 AU from the primary.


  1. ^ a b c Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M 
  2. ^ "Bos". 
  3. ^ (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.
  4. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 13 日