Lambda Ceti
Star in the constellation Cetus
From Wikipedia, the free encyclopedia
Lambda Ceti is a star in the equatorial constellation of Cetus. Its name is a Bayer designation that is Latinized from λ Ceti, and abbreviated Lambda Cet or λ Cet. Historically, the star bore the traditional name Menkar, although today that name is more commonly associated with α Ceti. With an apparent visual magnitude of 4.71,[1] it is faintly visible to the naked eye. Based on parallax measurement of 7.32 mas as seen from Earth, it is located at a distance of approximately 446 light-years (137 pc) from the Sun. The star is drifting further away with a line of sight velocity component of 10 km/s.[4]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Cetus[1] |
| Right ascension | 02h 59m 42.893s[2] |
| Declination | +08° 54′ 26.589″[2] |
| Apparent magnitude (V) | 4.71[1] |
| Characteristics | |
| Spectral type | B6III[3] |
| U−B color index | −0.471[1] |
| B−V color index | −0.109±0.006[1] |
| Astrometry | |
| Radial velocity (Rv) | 10.2±2.8[4] km/s |
| Proper motion (μ) | RA: 8.382 mas/yr[2] Dec.: −16.385 mas/yr[2] |
| Parallax (π) | 7.3207±0.1451 mas[2] |
| Distance | 446 ± 9 ly (137 ± 3 pc) |
| Absolute magnitude (MV) | −1.52[1] |
| Details | |
| Mass | 5.01±0.05[5] M☉ |
| Radius | 5.4[6] R☉ |
| Luminosity | 652[1] L☉ |
| Temperature | 13,940±710[7] K |
| Rotational velocity (v sin i) | 131[8] km/s |
| Age | 100-125[6] Myr |
| Other designations | |
| Menkar, λ Cet, 91 Cet, BD+08°455, FK5 1083, HD 18604, HIP 13954, HR 896, SAO 110889[9] | |
| Database references | |
| SIMBAD | data |
This star, along with α Cet (Menkar), γ Cet (Kaffaljidhma), δ Cet, μ Cet, ξ1 Cet and ξ2 Cet were Al Kaff al Jidhmah, "the Part of a Hand".[10]
In Chinese, 天囷 (Tiān Qūn), meaning Circular Celestial Granary, refers to an asterism consisting of λ Ceti, α Ceti, κ1 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 λ Ceti itself is 天囷三 (Tiān Qūn sān, English: the Third Star of Circular Celestial Granary.)[11]
Lambda Ceti is a blue giant star with stellar classification B6III. It is an estimated 100-125 million years old,[6] and is spinning rapidly with a projected rotational velocity of 131 km/s.[8] It has five[5] times the mass of the Sun and 5.4 times the Sun's radius. The star is radiating 920[6] times the Sun's luminosity at an effective temperature of 13,940 K.[7]