- Beta Tauri
-
Elnath, β Tau 
Elnath is the β star in Taurus (map: top left).Observation data
Epoch J2000 Equinox J2000Constellation Taurus Right ascension 05h 26m 17.5134s[1] Declination 28° 36′ 27.494″[1] Apparent magnitude (V) 1.68 [1] Characteristics Spectral type B7III [1] U−B color index -0.49 [1] B−V color index -0.13 [1] Variable type None Astrometry Radial velocity (Rv) 9.2 [1] km/s Proper motion (μ) RA: 23.28 [1] mas/yr
Dec.: -174.22 [1] mas/yrParallax (π) 24.89 ± 0.88[1] mas Distance 131 ± 5 ly
(40 ± 1 pc)Absolute magnitude (MV) -1.34 Details Mass 4.5 [2] M☉ Radius 5-6[2] R☉ Luminosity 700 [2] L☉ Temperature 13,600 [2] K Metallicity -0.10 Fe/H[1][3] Rotation 82 km/s [1][4] Age ? years Other designations Database references SIMBAD data Beta Tauri (β Tau, β Tauri) is the second brightest star in the constellation Taurus, with an apparent magnitude of 1.68.[1] Because it is on the boundary of Taurus and Auriga, it also has the redundant Bayer designation Gamma Aurigae (γ Aur), which today is rarely used. The star has the traditional name Elnath—a reference to "the butting" of the bull's horns.
Contents
Properties
Elnath's absolute magnitude is -1.34, similar to another Taurean star, Maia in the Pleiadian star cluster. Like Maia, Elnath is a B class giant with a luminosity 700 times solar.[2] However being approximately 130 light years distant compared to Maia's estimated 360 light years, Elnath ranks as the second brightest star in the constellation.
Uniquely positioned along the plane of our Milky Way Galaxy a few degrees west of the galactic anticenter, Elnath heralds a rich collection of nebulae and star clusters.[5] Relative to our Sun, β Tauri is notable for a high abundance of manganese, but little calcium and magnesium.[2][3] This star has begun to evolve away from the main sequence.
This star can be occulted by the moon. Such occultations occur when the moon's ascending node is near the vernal equinox, as is the case in 2007. Most occultations are visible only in parts of the Southern Hemisphere, because the star lies at the northern edge of the lunar occultation zone. Rarely, it may be occulted as far north as southern California.[6]
Double star
There is a faint star that appears close enough to Elnath for astronomers to consider it a double star. Its visual companion, known as BD+28 795B, has a PA of 239 degrees and is separated from the main star by 33.4 arcseconds.[7][8]
Etymology
Beta Tauri has the traditional name Elnath, El Nath, or Alnath, which comes from the Arabic word النطح an-naţħ, meaning "the butting" (i.e. the bull's horns). As in many other (but not all) Arabic star names, the article ال is transliterated literally as el, despite the fact that in Arabic pronunciation it is assimilated to the following n; it can also be omitted: Nath.
In Chinese, 五車 (Wǔ Chē), meaning Five Chariots, refers to an asterism consisting of β Tauri, ι Aurigae, Capella, β Aurigae and θ Aurigae.[9] Consequently, β Tauri itself is known as 五車五 (Wǔ Chē wǔ, English: the Fifth Star of Five Chariot.)[10]
See also
- Lists of stars in the constellation Taurus
- Class B Stars
- Beta Tauri in fiction
References
- ^ a b c d e f g h i j k l m "SIMBAD query result: ELNATH -- Star in double system". Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=elnath&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id. Retrieved 2010-03-07.
- ^ a b c d e f Professor James B. (Jim) Kaler. "ELNATH (Beta Tauri)". University of Illinois. http://stars.astro.illinois.edu/sow/elnath.html. Retrieved 2010-03-07.
- ^ a b Heacox, W. D. (1979). "Chemical abundances in Hg-Mn stars". Astrophysical Journal Supplement Series 41: 675. Bibcode 1979ApJS...41..675H. doi:10.1086/190637.
- ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contr. Oss. Astrof. Padova in Asiago 239. Bibcode 1970CoAsi.239....1B.
- ^ "Deep Auriga". Today's Astronomy Picture of the Day. 2010-03-05. http://apod.nasa.gov/apod/ap100305.html. Retrieved 2010-03-07.
- ^ Abrams Planetarium - Skywatcher's Diary
- ^ "CCDM (Catalog of Components of Double & Multiple stars (Dommanget+ 2002)". VizieR. Centre de Données astronomiques de Strasbourg. http://vizier.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J05263%2b2836B. Retrieved 2010-03-07.
- ^ "Al Nath". Alcyone Bright Star Catalogue. http://www.alcyone.de/SIT/mainstars/SIT000764.htm. Retrieved 2010-03-07.
- ^ (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) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
External links
- Jim Kaler's Stars:Elnath
- Image of Elnath from APOD
Bayer α (Aldebaran) • β (Elnath) • γ (Prima Hyadum) • δ¹ (Secunda Hyadum) • δ² • δ³ • ε (Ain) • ζ (Tien Kwan) • η (Alcyone) • θ¹ • θ² • ι • κ¹ • κ² • λ • μ • ν • ξ • ο • π • ρ • σ¹ • σ² • τ • υ • φ • χ • ψ • ω¹ • ω² • b • c • d • e • f • h • i • k • l • m • n • o • p • q (Taygeta) • r • s • t • u • A¹ • A²Flamsteed 1 (ο) • 2 (ξ) • 4 (s) • 5 (f) • 6 (t) • 7 • 9 • 10 • 11 • 12 • 13 • 14 • 16 (Celaeno) • 17 (Electra) • 18 • 19 (q, Taygeta) • 20 (Maia) • 21 (Asterope I) • 22 (Asterope II) • 23 (Merope) • 24 • 25 (η, Alcyone) • 26 • 27 (Atlas) • 28 (Pleione) • 29 (u) • 30 (e) • 31 • 32 • 33 • 35 (λ) • 36 • 37 (A¹) • 38 (ν) • 39 (A²) • 40 • 41 • 42 (ψ) • 43 (ω¹) • 44 (p) • 45 • 46 • 47 • 48 • 49 (μ) • 50 (ω²) • 51 • 52 (φ) • 53 • 54 (γ, Prima Hyadum) • 55 • 56 • 57 (h) • 58 • 59 (χ) • 60 • 61 (δ¹, Secunda Hyadum) • 62 • 63 • 64 (δ²) • 65 (κ¹) • 66 (r) • 67 (κ²) • 68 (δ³) • 69 (υ) • 70 • 71 • 72 • 73 (π) • 74 (ε, Ain) • 75 • 76 • 77 (θ¹) • 78 (θ²) • 79 (b) • 80 • 81 • 83 • 84 • 85 • 86 (ρ) • 87 (α, Aldebaran) • 88 (d) • 89 • 90 (c¹) • 91 (σ¹) • 92 (σ²) • 93 • 94 (τ) • 95 • 96 • 97 (i) • 98 (k) • 99 • 101 • 102 (ι) • 103 • 104 (m) • 105 • 106 (l) • 107 • 108 • 109 (n) • 110 • 111 • 112 (β, Elnath) • 113 • 114 (o) • 115 • 116 • 117 • 118 • 119 • 120 • 121 • 122 • 123 (ζ, Tien Kwan) • 125 • 126 • 127 • 128 • 129 • 130 • 131 • 132 • 133 • 134 • 135 • 136 • 137 • 139 • 140 • 44 Eri • 49 EriNearby WISE 0410+1502 • Gliese 176Other Categories:- Taurus constellation
- Auriga constellation
- Bayer objects
- B-type giants
- Stars with proper names
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