Phi Capricorni
Star in the constellation Capricornus
From Wikipedia, the free encyclopedia
Phi Capricorni is a solitary[11] star in the southern constellation of Capricornus. Its name is a Bayer designation that is Latinized from φ Capricorni, and abbreviated Phi Cap or φ Cap. This star 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 approximately 670 light years from the Sun, give or take 20 light years. Because of its proximity to the ecliptic, it is subject to lunar occultation.[12]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 21h 15m 37.900s[1] |
| Declination | −20° 39′ 06.10″[1] |
| Apparent magnitude (V) | +5.16[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch (86%)[3] |
| Spectral type | K0 II-III[4] |
| B−V color index | +1.15[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.5±0.5[5] km/s |
| Proper motion (μ) | RA: +13.850 mas/yr[1] Dec.: −2.682 mas/yr[1] |
| Parallax (π) | 4.8754±0.1154 mas[1] |
| Distance | 670 ± 20 ly (205 ± 5 pc) |
| Absolute magnitude (MV) | −1.16±0.107[6] |
| Details | |
| Mass | 2.63[7] M☉ |
| Radius | 35[8] R☉ |
| Luminosity | 447[7] L☉ |
| Surface gravity (log g) | 1.77[6] cgs |
| Temperature | 4,490±25[7] K |
| Metallicity [Fe/H] | −0.15[6] dex |
| Rotational velocity (v sin i) | 3.8[9] km/s |
| Age | 1.24[7] Gyr |
| Other designations | |
| φ Cap, 28 Cap, BD−21°5974, HD 202320, HIP 104963, HR 8127, SAO 190173[10] | |
| Database references | |
| SIMBAD | data |
This is an evolved, orange-hued K-type giant/bright giant star with a stellar classification of K0 II-III[4] It shows an infrared excess, which may be due to leftover material from a mass-loss event.[9] The star has an estimated 2.63 times the mass of the Sun,[7] and radiates 447 times the solar luminosity from its photosphere at an effective temperature of 4,490 K.[7] Phi Capricorni is around 1.24[7] billion years old and is spinning with a projected rotational velocity of 3.8 km/s.[9]
Chinese Name
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.[13] Consequently, the Chinese name for φ Capricorni itself represents the state Chu (楚),[14] together with ε Ophiuchi in Right Wall of Heavenly Market Enclosure (asterism).[15][16]
R. H. Allen had the opinion that φ Capricorni, together with χ Capricorni, represented the state Wei (魏).[16]