The location of ε Arae (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ara |
| Right ascension | 16 59 35.04880 |
| Declination | –53° 09′ 37.5713″ |
| Apparent magnitude (V) | +4.068 |
| Characteristics | |
| Spectral type | K3 III |
| U−B color index | +1.71 |
| B−V color index | +1.45 |
| Astrometry | |
| Radial velocity (Rv) | +23.1 km/s |
| Proper motion (μ) | RA: +2.16 mas/yr Dec.: +22.04 mas/yr |
| Parallax (π) | 9.04 ± 0.27 mas |
| Distance | 360 ± 10 ly (111 ± 3 pc) |
| Absolute magnitude (MV) | –0.79 ± 0.16 |
| Details | |
| Mass | 1.74 ± 0.24 M☉ |
| Radius | 33.7 ± 3.4 R☉ |
| Surface gravity (log g) | 1.80 cgs |
| Temperature | 4,176 K |
| Metallicity | 0.08 ± 0.05 dex |
| Age | 1.70 ± 0.57 Gyr |
| Other designations | |
| CPD–52° 10372, FK5 632, HD 152980, HIP 83153, HR 6295, SAO 244331. | |
| Database references | |
| SIMBAD | data |
Epsilon Arae (ε Ara, ε Arae) is the Bayer designation for a star in the constellation Ara, the Altar. It is visible to the naked eye with an apparent visual magnitude of +4.1 Based upon an annual parallax shift of 9.04 mas, this star is around 360 light-years (110 parsecs) distant from the Earth.
ε Arae is an evolved giant star with a stellar classification of K3 III. It is around 74% more massive than the Sun. At an age of about 1.7 billion years, the outer envelope of the star has expanded to almost 34 times the Sun's radius. It is radiating energy into space at an effective temperature of 4,176 K, giving it the orange-hued glow of a K-type star.
ε Arae was known as 龜一(spelled as "Guī yī", meaning: "the 1st (star) of Guī") in traditional Chinese astronomy. Allen erroneously called it Tso Kang (左更). He probably confused the constellation "Ara" with "Ari", as Tso Kang is actually in Aries.
References
- ^ van Leeuwen, F. (November 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.
- ^ Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
- ^ Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
- Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1.
- ^ da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088.
- "eps01 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-28.
{{cite web}}: CS1 maint: postscript (link) - "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-07-21.
- ^ Chevalier, S., and Tsuchihashi, P., (1911): "Catalogue d'Étoiles fixes, observés a Pekin sous l'Empereur Kien Long (Qianlong (Chien-Lung)), XVIII siecle", Annales de l'Observatoire Astronomique de Zô-Sé.
- ^ 伊世同 (Yi Shi Tong) (1981): 『中西対照恒星図表』科学出版社.(in Chinese)
- Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 64, ISBN 0-486-21079-0.
Further reading
- 大崎正次 (1987): 「中国の星座・星名の同定一覧表」『中国の星座の歴史』 雄山閣出版, pp. 312, 326.(in Japanese)
External links
- Simbad Epsilon Arae
- Image Epsilon Arae
- AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 1 日 Archived 2011-09-28 at the Wayback Machine(in Chinese)
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