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.

Iota Ceti
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[1] mas
Distance275 ± 4 ly
(84 ± 1 pc)
Absolute magnitude (MV)−1.2[7]
Details[6]
Mass2.78[3] M☉
Radius34 R☉
Luminosity398 L☉
Surface gravity (log g)2.1 cgs
Temperature4,446±18 K
Metallicity [Fe/H]−0.09 dex
Rotational velocity (v sin i)0.4 km/s
Age2.23[3] Gyr
Other designations
ι Cet, 8 Cet, BD−09° 48, FK5 9, HD 1522, HIP 1562, HR 74, SAO 128694.[8]
Database references
SIMBADdata

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
  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. "iot Cet -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-02-06.
  9. Bakich, Michael E. (1995), The Cambridge Guide to the Constellations, Cambridge University Press, p. 116, ISBN 0521449219.
  10. (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.
  11. (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2009-09-29 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  12. Garcia, B. (June 1989), "A list of MK standard stars", Bulletin d'Information du Centre de Données Stellaires, 36: 27, Bibcode:1989BICDS..36...27G.
  13. 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.
  14. 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.
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