Eta Ursae Minoris

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η Ursae Minoris
Ursa Minor IAU.svg
Cercle rouge 100%.svg

Merak in Ursa Major.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Minor
Right ascension 16h 17m 30.3s
Declination +75° 45' 19"
Apparent magnitude (V) +4.95
Absolute magnitude (V) +2.61[1]
Distance 97.3 ± 1.4 ly
(29.8 ± 0.4 pc)
Spectral type F5 V
Other designations
21 Ursae Minoris, NN 3950, HR 6116, HD 148048, BD+76 596, FK5 612, HIP 79822, SAO 8470, GC 21999, CCDM 16176+7545

Eta Ursae Minoris (η UMi, η Ursae Minoris) is a star in the constellation Ursa Minor. It has the traditional names Anwar al Farkadain and Alasco.[citation needed] The first is from the Arabic أنور الفرقدين ’anwar al-farqadayn "the brighter of the two calves", as opposed to Ahfa al Farkadain (ζ UMi) "the dimmer of the two calves";[citation needed] these names were originally applied to Kochab, and Pherkad, respectively, the other two stars in the rectangle of Ursa Minor.

Eta Ursae Minoris is a yellow-white F-type main sequence dwarf of spectral type F5V with an apparent magnitude of +4.95,[2] making it visible to the naked eye.[3] It is approximately 97 light years from Earth.[2]

This star has 1.41 times the mass of the Sun, with a projected rotational velocity of 76.0 km s−1.[1]

References[edit]

  1. ^ a b Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics 361: 614–628, Bibcode:2000A&A...361..614P 
  2. ^ a b SIMBAD, Eta Ursae Minoris (accessed 30 July 2014)
  3. ^ Kaler, James B. "Anwar al Farkadain". Stars. University of Illinois. Retrieved 21 June 2014.