Star in the constellation Cancer
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
^ 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 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 .
^ 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
^ 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
^ 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.
^ 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
^ "* eta Cnc" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2015-10-07 .
^ 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 .
^ 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 .