| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h12m 59.99769s[1] |
| Declination | +08° 50′ 48.2023″[1] |
| Apparent magnitude (V) | +4.36[2] [combined] |
| Characteristics | |
| Spectral type | G7III Ba0.4 Fe-1[3] + DA4[4] |
| B−V color index | 0.878±0.024[2] |
| Astrometry | |
| Radial velocity (Rv) | −3.93±0.09[2] km/s |
| Proper motion (μ) | RA: −24.498[1] mas/yr Dec.: −5.952[1] mas/yr |
| Parallax (π) | 9.5451 ± 0.3275 mas[1] |
| Distance | 340 ± 10 ly (105 ± 4 pc) |
| Absolute magnitude (MV) | –0.99[5] |
| Orbit[6] | |
| Period (P) | 1,642.1±1.3 |
| Semi-major axis (a) | ≥ 0.896 ± 0.020 AU (134 ± 3 Gm) |
| Eccentricity (e) | 0 (fixed) |
| Periastron epoch (T) | 34,985±5 MJD |
| Semi-amplitude (K1) (primary) | 5.91±0.14 km/s |
| Details | |
| A | |
| Mass | 3.80[5] M☉ |
| Radius | 18.2+1.0 −2.4[1] R☉ |
| Luminosity | 209.9±8.2[1] L☉ |
| Surface gravity (log g) | 2.60[1] cgs |
| Temperature | 5,184±50[5] K |
| Metallicity [Fe/H] | −0.01[5] dex |
| Age | 100[7] Myr |
| B | |
| Mass | 0.8[5] M☉ |
| Surface gravity (log g) | 8.4[8] cgs |
| Other designations | |
ξ1 Cet, ksi01 Cet, 65 Ceti, NSV 749, BD+08° 345, HD 13611, HIP 10324, HR 649, SAO 110408, WDS 02130+0851, WD 02130+0851[9] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Xi1 Ceti , Latinized from ξ1 Ceti, is a binary star[10] system located in the equatorial constellationofCetus. It is visible to the naked eye with a combined apparent visual magnitude of +4.36.[2] The distance to this system is approximately 340 light years based on parallax measurements, and it is drifting closer to the Sun with a radial velocity of −4 km/s.[2] The proximity of the star to the ecliptic means it is subject to lunar occultations.[11]
The spectroscopic binary nature of Xi1 Ceti was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory.[12][6] The pair have a circular orbit with a period of 4.5 years and a separation of 3.8 AU.[5] It is a suspected eclipsing binary with an amplitude of 0.03 in magnitude, which would suggest the orbital plane has a high inclination.[13]
The primary, designated component A, is a mild barium[14] giant star with a stellar classificationofG7III Ba0.4 Fe-1.[3] Morgan and Keenan in 1973 had classified it as a bright giant star with an anomalous underabundance of the CN molecule.[15] Evidence has been found for an overabundance of s-process elements,[5] although this is disputed.[7] The star has 3.8[5] times the mass and 18[1] times the radius of the Sun. The companion, component B, is a small white dwarf companion with 80% of the mass of the Sun and a class of DA4.[4] It was detected in 1985 by its ultraviolet emission.[8]
InChinese, 天囷 (Tiān Qūn), meaning Circular Celestial Granary, refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for Xi1 Ceti itself is "the Fifth Star of Circular Celestial Granary", Tiān Qūn Wu.[16]
{{cite web}}: CS1 maint: postscript (link)
