- Beta Ursae Majoris
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β Ursae Majoris 
Merak in Ursa Major.Observation data
Epoch J2000.0 Equinox J2000.0Constellation Ursa Major Right ascension 11h 01m 50.5s Declination +56° 22′ 57″ Apparent magnitude (V) +2.34 Characteristics Spectral type A1V U−B color index 0.01 B−V color index -0.02 Variable type suspected Astrometry Radial velocity (Rv) -12 km/s Proper motion (μ) RA: 81.66 mas/yr
Dec.: 33.74 mas/yrParallax (π) 41.07 ± 0.60 mas Distance 79 ± 1 ly
(24.3 ± 0.4 pc)Absolute magnitude (MV) 0.41 Details Mass 3 M☉ Radius 2 R☉ Luminosity 69 L☉ Temperature 9800 K Metallicity ? Rotation ~39 km/s. Age ? years Other designations Coordinates:
11h 01m 50.5s, +56° 22′ 57″ Beta Ursae Majoris (β UMa, β Ursae Majoris) is a star in the constellation of Ursa Major. It has the traditional name Merak.It is more familiar to northern hemisphere observers as one of the "pointer stars" in the Big Dipper, and a straight line connecting it with nearby Alpha Ursae Majoris (Dubhe) extends to Polaris, the north star. It is also one of the five stars in the Big Dipper asterism that form a part of a loose open cluster called the Ursa Major moving group, sharing the same region of space and not just the same patch of sky by our perspective.
Merak is fairly typical for a main sequence star of its type, although being slightly hotter and larger than our own Sun, it shines several times brighter. It is surrounded by a cooling disk of dust, much like those discovered around Fomalhaut and Vega. No planets have been discovered orbiting Merak, but the presence of the dust indicates they may exist or be in the process of forming.
The name is derived from the Arabic المراق al-maraqq "the loins" (of the bear).
Book plate by Sydney Hall depicting Ursa Major's stars
Merak in Military
USS Merak (1918) and USS Merak (AF-21), both of United States navy ship.
Stars of Ursa Major Bayer α (Dubhe) • β (Merak) • γ (Phecda) • δ (Megrez) • ε (Alioth) • ζ (Mizar) • η (Alkaid) • θ (Alhaud) • ι (Talitha Bor) • κ (Talitha Aus) • λ (Tania Bor) • μ (Tania Aus) • ν (Alula Bor) • ξ (Alula Aus) • ο (Muscida) • π¹ • π² • ρ • σ¹ • σ² • τ • υ • φ • χ • ψ • ω • b • c • d • e • f • g (Alcor) • h • AFlamsteed 1 (ο, Muscida) • 2 (A) • 3 (π¹) • 4 (π²) • 5 (b) • 6 • 7 • 8 (ρ) • 9 (ι, Talitha Bor) • 11 (σ¹) • 12 (κ, Talitha Aus) • 13 (σ²) • 14 (τ) • 15 (f) • 16 (c) • 17 • 18 (e) • 19 • 20 • 21 • 22 • 23 (h) • 24 (d) • 25 (θ, Alhaud) • 26 • 27 • 28 • 29 (υ) • 30 (φ) • 31 • 32 • 33 (λ, Tania Bor) • 34 (μ, Tania Aus) • 35 • 36 • 37 • 38 • 39 • 40 • 41 • 42 • 43 • 44 • 45 (ω) • 46 • 47 • 48 (β, Merak) • 49 • 50 (α, Dubhe) • 51 • 52 (ψ) • 53 (ξ, Alula Aus) • 54 (ν, Alula Bor) • 55 • 56 • 57 • 58 • 59 • 60 • 61 • 62 • 63 (χ) • 64 (γ, Phecda) • 65 • 66 • 67 • 68 • 69 (δ, Megrez) • 70 • 71 • 72 • 73 • 74 • 75 • 76 • 77 (ε, Alioth) • 78 • 79 (ζ, Mizar) • 80 (g, Alcor) • 81 • 82 • 83 • 84 • 85 (η, Alkaid) • 86 • 55 Cam • 56 Cam • 57 Cam • 1 CVn • 14 LMi • 15 LMi • 47 LMi • 37 Lyn • 41 Lyn • 44 LynNearby Lalande 21185 • WISE 1405+5534 • Gliese 412 • Groombridge 1618 • Gliese 338 • GJ 1151 • ξ (Alula Aus) • Gliese 450 • Gliese 424 • Groombridge 1830Other R • S • W • Winnecke 4Categories:- Bayer objects
- Henry Draper Catalogue objects
- Ursa Major constellation
- A-type main sequence stars
- Stars with proper names
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