- Gamma Arietis
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γ¹ Arietis Observation data
Epoch J2000 Equinox J2000Constellation Aries Right ascension 01h 53m 31.8s Declination +19° 17′ 45.0″ Apparent magnitude (V) 4.7 Characteristics Spectral type B9V Astrometry Radial velocity (Rv) 3.7 km/s Proper motion (μ) RA: 79 mas/yr
Dec.: -112 mas/yrParallax (π) 21 ± 5 mas Distance approx. 160 ly
(approx. 50 pc)Absolute magnitude (MV) 4.8 Details Rotational velocity (v sin i) 152 km/s km/s Other designations Database references SIMBAD data ARICNS data Data sources: Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)Gamma Arietis (γ Ari, γ Arietis) is a triple star system, 204 light years distant, in the constellation Aries. It has the traditional name Mesarthim, of obscure origin, and has been called "the First Star in Aries" as having been at one time the nearest visible star to the equinoctial point. The name Mesarthim was from the Hebrew word mᵋshārᵋtīm, meaning "the minister"[1], or the Arabic word Al Muthartim (ألمثرتم), meaning "the extremely fat ram".[2]
In Chinese, 婁宿 (Lóusù), meaning Bond (asterism), refers to an asterism consisting of γ Arietis, β Arietis and α Arietis.[3] Consequently, α Arietis itself is known as 婁宿二 (Lóusù Èr, English: the Second Star of Bond.)[4]
The system includes a binary star with components separated with an angular distance of 7.7 arcseconds (separable in small telescopes). Both components are white A-type main sequence stars and have apparent magnitudes of +4.75 and +4.83. The brighter is known as γ² Arietis and the dimmer γ¹ Arietis. The orbital period of the binary is greater than 5000 years. Orbiting the binary is γ Arietis C, a magnitude +9.6 K-type star located 221 arcseconds distant.
Robert Hooke discovered that Gamma Arietis was made of multiple stars in 1664.[5]
γ2 Arietis
γ2 Arietis Observation data
Epoch J2000 Equinox J2000Constellation Aries Right ascension 01h 53m 31.83s Declination +19° 17′ 37.2″ Apparent magnitude (V) 4.64 Characteristics Spectral type A1p U−B color index -0.13 B−V color index -0.04 R−I color index -0.05 Variable type Alpha² CVn variable Astrometry Radial velocity (Rv) -0.6 km/s Proper motion (μ) RA: 80 mas/yr
Dec.: -104 mas/yrParallax (π) 21 ± 5 mas Distance approx. 160 ly
(approx. 50 pc)Absolute magnitude (MV) 4.71 Details Mass 3.1 M☉ Radius 2.1 R☉ Luminosity 40 L☉ Temperature 7,500–10,000 K Rotational velocity (v sin i) 63 Km/s km/s Other designations Database references SIMBAD data Data sources: Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)The brightest component, γ² Arietis, is classified as an Alpha2 Canum Venaticorum type variable star and its brightness varies by 0.04 magnitudes with a period of 2.61 days.
References
- ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 82. ISBN 0486210790. http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Aries*.html. Retrieved 2010-12-12.
- ^ Davis Jr., G. A., "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names,"Popular Astronomy, Vol. LII, No. 3, Oct. 1944, p. 13.
- ^ (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.
- ^ Aitken, Robert G. (1935). The Binary Stars. New York: McGraw-Hill. pp. 1.
Bayer Flamsteed 1 • 4 • 5 (γ, Mesarthim) • 6 (β, Sheratan) • 7 • 8 (ι) • 9 (λ) • 10 • 11 • 12 (κ) • 13 (α, Hamal) • 14 • 15 • 16 • 17 (η) • 19 • 20 • 21 • 22 (θ) • 23 • 24 (ξ) • 26 • 27 • 29 • 30 • 31 • 32 (ν) • 33 • 34 (μ) • 35 • 36 • 37 (ο) • 38 • 39 • 40 • 41 (c, Bharani) • 42 (π) • 43 (σ) • 44 (ρ¹) • 45 (ρ²) • 46 (ρ³) • 47 • 48 (ε) • 49 • 50 • 51 • 52 • 53 • 54 • 55 • 56 • 57 (δ, Botein) • 58 (ζ) • 59 • 60 • 61 (τ¹) • 62 • 63 (τ²) • 64 • 65 • 66 • 54 Cet • 85 CetNearby Teegarden's star • TZ • Gliese 109 • GJ 3146Categories:- Multiple star stubs
- Variable star stubs
- Henry Draper Catalogue objects
- Binary stars
- HIP objects
- Aries constellation
- Bayer objects
- Alpha2 Canum Venaticorum variables
- Triple star systems
- A-type main sequence stars
- Type-K stars
- Stars with proper names
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