Phi1 Ceti
Star in the constellation Cetus
From Wikipedia, the free encyclopedia
Phi1 Ceti is a single[10] star located in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of +4.78. Based upon an annual parallax shift of 15.1 mas,[1] it is located about 216 light-years (66 pc) from the Sun. Based upon the motion of this star through space, Phi1 Ceti is a probable member of the proposed Wolf 630 moving group. This is a set of stars centered on Wolf 630 that are moving nearly in parallel and have an age of around 2.7±0.5 billion years. They may be former members of a dissolved open cluster.[11]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 44m 11.400s[1] |
| Declination | â10° 36â² 34.383â³[1] |
| Apparent magnitude (V) | 4.75[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0 III[4] |
| UâB color index | +0.83[2] |
| BâV color index | +1.00[2] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | +0.33±0.63[6] km/s |
| Proper motion (μ) | RA: â9.323 mas/yr[1] Dec.: â113.192 mas/yr[1] |
| Parallax (Ï) | 15.1265±0.1043 mas[1] |
| Distance | 216 ± 1 ly (66.1 ± 0.5 pc) |
| Absolute magnitude (MV) | 0.732[7] |
| Details[6] | |
| Mass | 1.60[8] Mâ |
| Radius | 11 Râ |
| Luminosity | 54 Lâ |
| Surface gravity (log g) | 2.7 cgs |
| Temperature | 4,775±5 K |
| Metallicity [Fe/H] | â0.16 dex |
| Rotational velocity (v sin i) | 2.3 km/s |
| Age | 2.21[8] Gyr |
| Other designations | |
| Ï1 Cet, 17 Ceti, NSV 278, BDâ11°128, FK5 2048, HD 4188, HIP 3455, HR 194, SAO 147423[9] | |
| Database references | |
| SIMBAD | data |
At an age of about 2.21[8] billion years, Phi1 Ceti is an evolved red clump[3] giant star with a stellar classification of K0 III.[4] It is presently on the horizontal branch and is generating energy through the nuclear fusion of helium at its core. The star is suspected of variability; it has been measured to vary between magnitudes 4.75 and 4.78.[5] It has 1.6[8] times the mass of the Sun and has expanded to 11 times the Sun's radius. The star is radiating 54 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,775 K.[6]