Eta Cancri, Latinized from η Cancri, is a single,[8] orange-hued star in the zodiac constellation of Cancer. It is a faint star but visible to the naked eye with an apparent visual magnitude of 5.34.[2] The annual parallax shift of 10.93[1] mas as seen from Earth yields a distance estimate of 155 light years from the Sun. It is moving further away with a radial velocity of +22 km/s.[3]

A stellar classification of K3 III[2] for Eta Cancri indicates that, at the estimated age of 3.9 billion years old,[5] it has left the main sequence and become an evolved giant star. The spectrum shows unusually strong absorption lines of cyanogen.[2] It has 1.5[5] times the mass of the Sun and has expanded to 17[6] times the Sun's radius. The star is radiating 87[5] times the Sun's luminosity from its photosphere at an effective temperature of around 4,415 K.[5]

In Chinese astronomy, Ghost (Chinese: 鬼宿; pinyin: Guǐ Xiù) refers to an asterism consisting of Theta Cancri, Eta Cancri, Gamma Cancri and Delta Cancri.[9] Eta Cancri itself is the second star of Ghost (Chinese: 鬼宿二; pinyin: Guǐ Xiù èr), following the designation from its determinative star (θ Cnc) from east to west.

References

  1. ^ 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
  2. ^ a b c d e f g McClure, R. D. (February 1970). "A photometric investigation of strong-cyanogen stars". Astronomical Journal. 75: 41–52. Bibcode:1970AJ.....75...41M. doi:10.1086/110938.
  3. ^ a b Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
  4. ^ a b Luck, R. Earle; Heiter, Ulrike (June 2007), "Giants in the Local Region", The Astronomical Journal, 133 (6): 2464–2486, Bibcode:2007AJ....133.2464L, doi:10.1086/513194
  5. ^ a b c d e f g h 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.
  6. ^ a b c d 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. ^ "* eta Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-10-07.
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  9. ^ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà 中國星座神話 [Chinese Constellation Mythology]. 台灣古籍出版有限公司. p. 394. ISBN 978-986-7332-25-7.
Allikas: Https://en.wikipedia.org/wiki/Eta_Cancri
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