Iota Ceti
Iota Ceti (ι Cet, ι Ceti) is the Bayer designation for a star system in the equatorial constellation of Cetus. It has the traditional name Deneb Kaitos Shemali.[9] The name was from the Arabic word ذنب قيطس الشمالي - dhanab qayṭas al-shamālī, meaning the northern tail of the sea monster. it is visible to the naked eye with an apparent visual magnitude of 3.562.[2] Based upon an annual parallax shift of 11.88 mas,[1] it lies around 275 light years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 19m 25.67416s[1] |
| Declination | −08° 49′ 26.1111″[1] |
| Apparent magnitude (V) | 3.562[2] |
| Characteristics | |
| Spectral type | K1.5 III[3] or K1 II + (K)[4] |
| U−B color index | +1.278[2] |
| B−V color index | +1.212[2] |
| Variable type | Suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | +19.35±0.17[6] km/s |
| Proper motion (μ) | RA: −15.15[1] mas/yr Dec.: −37.11[1] mas/yr |
| Parallax (π) | 11.88 ± 0.18 mas[1] |
| Distance | 275 ± 4 ly (84 ± 1 pc) |
| Absolute magnitude (MV) | −1.2[7] |
| Details[6] | |
| Mass | 2.78[3] M☉ |
| Radius | 34 R☉ |
| Luminosity | 398 L☉ |
| Surface gravity (log g) | 2.1 cgs |
| Temperature | 4,446±18 K |
| Metallicity [Fe/H] | −0.09 dex |
| Rotational velocity (v sin i) | 0.4 km/s |
| Age | 2.23[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
In Chinese, 天倉 (Tiān Cāng), meaning Square Celestial Granary, refers to an asterism consisting of ι Ceti, η Ceti, θ Ceti, ζ Ceti, τ Ceti and 57 Ceti.[10] Consequently, the Chinese name for ι Ceti itself is 天倉一 (Tiān Cāng yī, English: the First Star of Square Celestial Granary.)[11]
This is an MK-standard star with a stellar classification of K1.5 III,[12] indicating that it is an evolved K-type giant star. However, Houk and Swift (1999) list a classification of K1 II,[4] which would indicate this is a bright giant. It is a suspected variable with a visual amplitude of around 0.05 magnitude.[5] The star has about 2.8[3] times the mass of the Sun, 34 times the Sun's radius, and radiates 398 times the solar luminosity from its outer atmosphere at an effective temperature of 4,446 K.[6]
Iota Ceti forms a wide astrometric pair with a common proper motion companion,[13] a magnitude 10.40 star at an angular separation of 106.4 arcseconds along a position angle of 191° (as of 2014).[14] This companion may be a K-type star.[4]
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.
- ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- ^ a b c d Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
- ^ a b c Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, 5, Bibcode:1999MSS...C05....0H.
- ^ a b Eggen, O. J. (July 1993), "Evolved GK stars near the sun. I - The old disk population", Astronomical Journal, 106 (1): 80–132, Bibcode:1993AJ....106...80E, doi:10.1086/116622. See p. 97.
- ^ a b c Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209, S2CID 121883397.
- ^ Ryon, Jenna; et al. (August 2009), "Comparing the Ca ii H and K Emission Lines in Red Giant Stars", Publications of the Astronomical Society of the Pacific, 121 (882): 842, arXiv:0907.3346, Bibcode:2009PASP..121..842R, doi:10.1086/605456, S2CID 17821279.
- ^ "iot Cet -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-02-06.
- ^ Bakich, Michael E. (1995), The Cambridge Guide to the Constellations, Cambridge University Press, p. 116, ISBN 0521449219.
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 2009-09-29 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ Garcia, B. (June 1989), "A list of MK standard stars", Bulletin d'Information du Centre de Données Stellaires, 36: 27, Bibcode:1989BICDS..36...27G.
- ^ Gontcharov, G. A.; et al. (2001), "The proper motions of fundamental stars. I. 1535 stars from the Basic FK5", Astronomy and Astrophysics, 365 (2): 222, Bibcode:2001A&A...365..222G, doi:10.1051/0004-6361:20000010.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.