Lambda Aquarii
 
| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 52m 36.87441s[1] |
| Declination | −07° 34′ 46.5542″[1] |
| Apparent magnitude (V) | 3.722[2] |
| Characteristics | |
| Spectral type | M2.5 IIIa Fe–1[3] |
| U−B color index | +1.721[2] |
| B−V color index | +1.641[2] |
| Variable type | Lb[4] |
| Astrometry | |
| Radial velocity (Rv) | −10.46 ± 0.53[5] km/s |
| Proper motion (μ) | RA: +17.02[1] mas/yr Dec.: +33.03[1] mas/yr |
| Parallax (π) | 8.47 ± 0.66[1] mas |
| Distance | 390 ± 30 ly (118 ± 9 pc) |
| Absolute magnitude (MV) | –1.5[6] |
| Details | |
| Mass | 3.6[7] M☉ |
| Temperature | 3,835[7] K |
| Metallicity [Fe/H] | –2.25[6] dex |
| Other designations | |
Lambda Aquarii (λ Aqr, λ Aquarii) is the Bayer designation for a star in the equatorial constellation of Aquarius. The apparent visual magnitude of this star is 3.722,[2] which is bright enough to be visible with the naked eye. It is roughly 390 light-years (120 pc) from Earth.[1]
In Chinese, 壘壁陣 (Lěi Bì Zhèn), meaning Line of Ramparts, refers to an asterism consisting of λ Aquarii, κ Capricorni, ε Capricorni, γ Capricorni, δ Capricorni, ι Aquarii, σ Aquarii, φ Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium.[9] Consequently, λ Aquarii itself is known as 壘壁陣七 (Lěi Bì Zhèn qī, English: the Seventh Star of Line of Ramparts.)[10]
Lambda Aquarii is a red giant star with a stellar classification of M2.5 III.[3] It is classified as slow irregular variable and pulsation periods of 24.5, 32.0, and 49.5 days have been identified.[11] This star is on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.[12]
References
- 1 2 3 4 5 6 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. - 1 2 3 4 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publ. Dept. Astron. Univ. Chile, Publicaciones Universidad de Chile, Department de Astronomy, 1: 1–17, Bibcode:1966PDAUC...1....1G.
- 1 2 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.
- ↑ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ↑ Famaey, B.; et al. (May 2009), "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698.
- 1 2 Dupree, A. K.; Li, Timothy Q.; Smith, Graeme H. (October 2007), "Hubble Space Telescope Observations of Chromospheres in Metal-Deficient Field Giants", The Astronomical Journal, 134 (4): 1348–1359, arXiv:0709.1709, Bibcode:2007AJ....134.1348D, doi:10.1086/520925.
- 1 2 Tsuji, Takashi (May 2007). "Isotopic abundances of Carbon and Oxygen in Oxygen-rich giant stars". In Kupka, F.; Roxburgh, I.; Chan, K. Convection in Astrophysics, Proceedings of IAU Symposium #239 held 21-25 August, 2006 in Prague, Czech Republic. Proceedings of the International Astronomical Union. 2. pp. 307–310. arXiv:astro-ph/0610180. Bibcode:2007IAUS..239..307T. doi:10.1017/S1743921307000622.
- ↑ "lam Aqr -- Pulsating variable Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-01.
- ↑ (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.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日
- ↑ Tabur, V.; et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–1961, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x.
- ↑ Lebzelter, T.; Hron, J. (January 2008), "BRITE stars on the AGB", Communications in Asteroseismology, 152: 178–181, Bibcode:2008CoAst.152..178L, doi:10.1553/cia152s178.