Alioth

For other uses, see Alioth (disambiguation).
Alioth
Location of Alioth (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 12h 54m 01.74959s[1]
Declination +55° 57′ 35.3627″[1]
Apparent magnitude (V) 1.77[2]
Characteristics
Spectral type A1III-IVp kB9
U−B color index +0.02[2]
B−V color index −0.02[2]
Variable type α2 CVn
Astrometry
Radial velocity (Rv)−9.3[3] km/s
Proper motion (μ) RA: +111.91 mas/yr[1]
Dec.: −8.24 mas/yr[1]
Parallax (π)39.51 ± 0.20 mas[1]
Distance82.6 ± 0.4 ly
(25.3 ± 0.1 pc)
Absolute magnitude (MV)−0.2[4]
Details
Mass2.91[5] M☉
Radius4.29+0.19
−0.21[6] R☉
Luminosity104.4±9.3[6] L☉
Surface gravity (log g)3.59[6] cgs
Temperature8,908±24[6] K
Metallicity [Fe/H]+0.00[4] dex
Rotational velocity (v sin i)33[7] km/s
Age300[8] Myr
Other designations
Alioth, Allioth, Aliath, ε UMa, 77 Ursae Majoris, BD+56°1627, FK5 483, GC 17518, HD 112185, HIP 62956, HR 4905, SAO 28553, PPM 33769
Database references
SIMBADdata

Alioth /ˈæliɒθ/, also called Epsilon Ursae Majoris, is a star in the northern constellation of Ursa Major. The designation is Latinised from ε Ursae Majoris and abbreviated Epsilon UMa or ε UMa.[9][10] Despite being designated "ε" (epsilon), it is the brightest star in the constellation and at magnitude 1.77 is the thirty-third brightest star in the sky.

It is the star in the tail of the bear closest to its body, and thus the star in the handle of the Big Dipper (or Plough) closest to the bowl. It is also a member of the large and diffuse Ursa Major moving group. Historically, the star was frequently used in celestial navigation in the maritime trade, because it is listed as one of the 57 navigational stars.[1]

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  4. ^ a b Cite error: The named reference aass77_1_41 was invoked but never defined (see the help page).
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  6. ^ a b c d Cite error: The named reference npoi was invoked but never defined (see the help page).
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  9. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  10. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.