Phi Capricorni (φ Cap, φ Capricorni) is a solitary[9] star in the southern constellation of Capricornus. It is visible to the naked eye with an apparent visual magnitude of +5.16.[2] Based upon an annual parallax shift of 5.07 mas as seen from the Earth,[1] the star is located about 640 light years from the Sun, give or take 30 light years.
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Capricornus |
Right ascension | 21h 15m 37.89982s[1] |
Declination | −20° 39′ 06.1032″[1] |
Apparent magnitude (V) | +5.16[2] |
Characteristics | |
Spectral type | K0 II-III[3] |
B−V color index | +1.15[2] |
Astrometry | |
Radial velocity (Rv) | −4.5±0.5[4] km/s |
Proper motion (μ) | RA: +15.01[1] mas/yr Dec.: −2.07[1] mas/yr |
Parallax (π) | 5.07 ± 0.25 mas[1] |
Distance | 640 ± 30 ly (197 ± 10 pc) |
Absolute magnitude (MV) | −1.16±0.107[5] |
Details | |
Mass | 2.63[6] M☉ |
Luminosity | 447[6] L☉ |
Surface gravity (log g) | 1.77[5] cgs |
Temperature | 4,490±25[6] K |
Metallicity [Fe/H] | −0.15[5] dex |
Rotational velocity (v sin i) | 3.8[7] km/s |
Age | 1.24[6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
This is an evolved, orange-hued K-type giant/bright giant star with a stellar classification of K0 II-III[3] It shows an infrared excess, which may be due to leftover material from a mass-loss event.[7] The star has an estimated 2.63 times the mass of the Sun,[6] and radiates 447 times the solar luminosity from its photosphere at an effective temperature of 4,490 K.[6] Phi Capricorni is around 1.24[6] billion years old and is spinning with a projected rotational velocity of 3.8 km/s.[7]
In Chinese, 十二國 (Shíer Guó), meaning Twelve States, refers to an asterism which is represent twelve ancient states in the Spring and Autumn period and the Warring States period, consisting of φ Capricorni, ι Capricorni, 38 Capricorni, 35 Capricorni, 36 Capricorni, χ Capricorni, θ Capricorni, 30 Capricorni, 33 Capricorni, ζ Capricorni, 19 Capricorni, 26 Capricorni, 27 Capricorni, 20 Capricorni, η Capricorni and 21 Capricorni.[10] Consequently, the Chinese name for φ Capricorni itself represents the state Chu (楚),[11] together with ε Ophiuchi in Right Wall of Heavenly Market Enclosure (asterism).[12][13]
R. H. Allen had opinion that φ Capricorni, together with χ Capricorni, represented the state Wei (魏).[13]