Eta Cancri
In today's article we are going to delve into the fascinating world of Eta Cancri. We will explore its origins, its impacts on today's society and its relevance in different areas. We will learn about its history, its distinctive characteristics and the possible future projections it could have. Eta Cancri is a topic of great interest and gives us the opportunity to delve deeper into its nature to better understand its influence on our environment. Join us on this journey of discovery and learning about Eta Cancri.
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 32m 42.49600s[1] |
| Declination | 20° 26′ 28.1865″[1] |
| Apparent magnitude (V) | 5.34[2] |
| Characteristics | |
| Spectral type | K3 III[2] |
| U−B color index | +1.40[2] |
| B−V color index | +1.25[2] |
| Astrometry | |
| Radial velocity (Rv) | +22.46[3] km/s |
| Proper motion (μ) | RA: −46.33[1] mas/yr Dec.: −44.31[1] mas/yr |
| Parallax (π) | 10.93±0.40 mas[1] |
| Distance | 300 ± 10 ly (91 ± 3 pc) |
| Absolute magnitude (MV) | +0.44[4] |
| Details | |
| Mass | 1.51[5] M☉ |
| Radius | 17[6] R☉ |
| Luminosity | 87[5] L☉ |
| Surface gravity (log g) | 2.1[6] cgs |
| Temperature | 4,415±57[5] K |
| Metallicity | 0.07±0.21[4] dex |
| Rotational velocity (v sin i) | 2.7[6] km/s |
| Age | 3.92[5] Gyr |
| Other designations | |
| η Cnc, 33 Cnc, BD+20° 2109, FK5 321, GC 11687, HD 72292, HIP 41909, HR 3366, SAO 80243[7] | |
| Database references | |
| SIMBAD | data |
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.
