Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star[10] system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7.[2] Based upon parallax measurements, the distance to this system is about 157 light-years (48 parsecs).[1] It is drifting closer to the Sun with a radial velocity of −9.1 km/s.[4]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 20h 52m 39.23277s[1] |
| Declination | −08° 58′ 59.9499″[1] |
| Apparent magnitude (V) | 4.731[2] |
| Characteristics | |
| Spectral type | A3m[3] |
| U−B color index | +0.149[2] |
| B−V color index | +0.322[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.1[4] km/s |
| Proper motion (μ) | RA: +45.75[1] mas/yr Dec.: -33.59[1] mas/yr |
| Parallax (π) | 20.74 ± 0.29 mas[1] |
| Distance | 157 ± 2 ly (48.2 ± 0.7 pc) |
| Absolute magnitude (MV) | +1.31[5] |
| Orbit[6] | |
| Period (P) | 1,566±3 d |
| Semi-major axis (a) | ≥ 67.06 Gm (0.4483 AU) |
| Eccentricity (e) | 0.23±0.19 |
| Periastron epoch (T) | 2,410,497±52 JD |
| Semi-amplitude (K1) (primary) | 3.2±0.6 km/s |
| Details | |
| A | |
| Radius | 3.54+0.45 −0.15[7] R☉ |
| Luminosity | 25.6±1.4[8] L☉ |
| Surface gravity (log g) | 3.99[8] cgs |
| Temperature | 6,906+151 −405[8] K |
| Rotational velocity (v sin i) | 53.7[8] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This star was tentatively identified as a single-lined spectroscopic binary by Helmut A. Abt in 1961.[11] It has an orbital period of 4.29 yr and an eccentricity (ovalness) of 0.23.[6] The pair have been resolved by speckle interferometry, showing an angular separation of 0.06″.[12] The visible spectrum matches a stellar classification of A3m, with the 'm' suffix indicating that this is an Am, or chemically peculiar star.[3] The primary has an estimated 3.5 times the Sun's radius and is radiating 26 times the luminosity of the Sun from its photosphere at an effective temperature of 6,906 km/s.[7]
This star together with ν Aquarii is Albulaan /ˌælbjəˈlɑːn/, derived from an Arabic term al-bulaʽān (ألبولعان) meaning "the two swallowers". This star, along with ε Aqr (Albali) and ν Aqr (Albulaan), were al Bulaʽ (البلع), the Swallower.[13][14] In Chinese, 女宿 (Nǚ Xiù), meaning Girl (asterism) (or Woman), refers to an asterism consisting of μ Aquarii, ε Aquarii, 4 Aquarii, 5 Aquarii and 3 Aquarii.[15] Consequently, the Chinese name for μ Aquarii itself is 女宿二 (Nǚ Xiù èr, English: the Second Star of Girl / Woman.)[16]
References
edit- ^ a b c d e f 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.
- ^ a b c d Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
- ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- ^ a b Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Abt, H. A.; Levy, S. G. (October 1985), "Improved study of metallic-line binaries", The Astrophysical Journal Supplement Series, 59: 229–247, Bibcode:1985ApJS...59..229A, doi:10.1086/191070.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377[permanent dead link]
- ^ "* 6 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-01.
- ^ 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.
- ^ Abt, Helmut A. (March 1961), "The Frequency of Binaries among Metalmc-Line Stars", The Astrophysical Journal Supplement Series, 6: 37, Bibcode:1961ApJS....6...37A, doi:10.1086/190060.
- ^ Hartkopf, William I.; et al. (2000), "ICCD Speckle Observations of Binary Stars. XXIII. Measurements during 1982-1997 from Six Telescopes, with 14 New Orbits", The Astronomical Journal, 119 (6): 3084, Bibcode:2000AJ....119.3084H, doi:10.1086/301402.
- ^ Davis Jr., G. A. (October 1944), "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names", Popular Astronomy, 52 (3): 12, Bibcode:1944PA.....52....8D.
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 53, ISBN 0-486-21079-0, retrieved 2010-12-12.
- ^ (in 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.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 14 日