Lambda Ceti
Lambda Ceti, Latinized from λ Ceti, is B-type star of fifth-magnitude located in the constellation Cetus. Historically, the star bore the traditional name Menkar, although today that name is more commonly associated with α Ceti.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 59m 42.89987s[1] |
| Declination | 08° 54′ 26.4899″[1] |
| Apparent magnitude (V) | 4.71[2] |
| Characteristics | |
| Spectral type | B6III[3] |
| U−B color index | −0.471[2] |
| B−V color index | −0.109±0.006[2] |
| Astrometry | |
| Radial velocity (Rv) | 10.2±2.8[4] km/s |
| Proper motion (μ) | RA: 6.01±0.26[1] mas/yr Dec.: −17.70±0.29[1] mas/yr |
| Parallax (π) | 5.66 ± 0.24 mas[1] |
| Distance | 580 ± 20 ly (177 ± 7 pc) |
| Absolute magnitude (MV) | −1.52[2] |
| Details | |
| Mass | 5.01±0.05[5] M☉ |
| Radius | 5.4[6] R☉ |
| Luminosity | 652[2] L☉ |
| Temperature | 13,940±710[7] K |
| Rotational velocity (v sin i) | 131[8] km/s |
| Age | 100-125[6] Myr |
| Other designations | |
| 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]
Properties Edit
Lambda Ceti is a blue giant star with stellar classification B6III. With five[5] times the mass of the Sun and an estimated radius that is 5.4 R☉, the star radiates a bolometric luminosity of about 920 L☉.[6] In 1997 the Hipparcos satellite estimated its parallax at 7.69 ± 0.76 milliarcseconds yielding a distance from Earth of about 130 ± 10 parsecs or 420 ± 40 light years. However recent astrometric calculations by van Leeuwen have placed the distance much farther at about 177 ± 7 pc or 580 ± 20 ly—a revaluation which significantly altered other stellar parameters.[1] Its apparent magnitude has been recently recalibrated at 4.6767 yielding an absolute magnitude of -1.56, almost as bright as its neighbor Alpha Ceti at -1.62.
References Edit
- ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.Vizier catalog entry
- ^ a b c d e Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
- ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ a b Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
- ^ a b c Kaler, James B. "LAMBDA CET (Lambda Ceti, the former "Menkar")". University of Illinois. Retrieved 2010-09-30.
- ^ Zorec, J.; et al. (2009). "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff". Astronomy and Astrophysics. 501 (1): 297–320. arXiv:0903.5134. Bibcode:2009A&A...501..297Z. doi:10.1051/0004-6361/200811147. S2CID 14969137.
- ^ Simón-Díaz, S.; et al. (January 2017), "The IACOB project. III. New observational clues to understand macroturbulent broadening in massive O- and B-type stars", Astronomy & Astrophysics, 597: 17, arXiv:1608.05508, Bibcode:2017A&A...597A..22S, doi:10.1051/0004-6361/201628541, S2CID 3478126, A22.
- ^ "lam Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-09-30.
- ^ Star Name - R.H. Allen p.160
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日