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Eta Ursae Majoris
Sign in to saveAlso known as Alkaid, 85 Ursae Majoris, HD 120315, The Twinkling Brilliance, 85 UMa, η Ursae Majoris, η UMa, SAO 44752
Alkaid , also called Eta Ursae Majoris (Latinised from η Ursae Majoris, abbreviated Eta UMa, η UMa), is a star in the constellation of Ursa Major. It is the easternmost star in the Big Dipper (or Plough) asterism. However, unlike most stars of the Big Dipper, it is not a member of the Ursa Major moving group. With an apparent visual magnitude of +1.86, it is the third-brightest star in the constellation and one of the brightest stars in the night sky.
Wikidata facts
- Instance of
- star
- Part of
- Big Dipper
- Constellation
- Ursa Major
- Distance from Earth
- 100
- Diameter
- 4730000
- Radius
- 3.4
- Image
- Ursa major star name.png
Show 15 more facts
- spectral class
- B3+V
- catalog code
- UBV M 19728
- stellar rotational velocity
- 226
- apparent magnitude
- 1.881019
- parallax
- 31.38
- right ascension
- 206.885157342
- declination
- 49.313266729
- effective temperature
- 17200
- Commons category
- Alkaid
- radial velocity
- -26.0
- right ascension component of proper motion
- -123
- epoch
- J2000.0
- surface gravity
- 14800
- absolute magnitude
- 0.67
- declination component of proper motion
- -16
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Encyclopedic overview
5 sectionsContents
- Physical properties
- Nomenclature
- In culture
- References
- External links
Alkaid , also called Eta Ursae Majoris (Latinised from η Ursae Majoris, abbreviated Eta UMa, η UMa), is a star in the constellation of Ursa Major. It is the easternmost star in the Big Dipper (or Plough) asterism. However, unlike most stars of the Big Dipper, it is not a member of the Ursa Major moving group. With an apparent visual magnitude of +1.86, it is the third-brightest star in the constellation and one of the brightest stars in the night sky.
==Physical properties== thumb|left|Comparison of Alkaid (left) and the Sun (right) Alkaid is a 10-million-year-old B-type main sequence star with a stellar classification of B3 V. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It has six times the mass; times the radius, and is radiating around 594 times as much energy as the Sun. Its outer atmosphere has an effective temperature of about 15,540 K, giving it the blue-white hue of a B-type star. This star is an X-ray emitter with a luminosity of .
Excerpted from Wikipedia’s “Eta Ursae Majoris” article, available under the CC BY-SA 4.0 licence.