Eta Ursae Majoris
From Wikipedia, the free encyclopedia
| Observation data Epoch J2000 |
|
|---|---|
| Constellation | Ursa Major |
| Right ascension | 13h 47m 32.4s |
| Declination | +49° 18′ 48″ |
| Apparent magnitude (V) | 1.85 |
| Characteristics | |
| Spectral type | B3 V |
| B-V color index | -0.19 |
| U-B color index | -0.67 |
| Variable type | ? |
| Astrometry | |
| Radial velocity (Rv) | -11 km/s |
| Proper motion (μ) | RA: -121.23 mas/yr Dec.: -15.56 mas/yr |
| Parallax (π) | 32.39 ± 0.74 mas |
| Distance | 101 ± 2 ly (30.9 ± 0.7 pc) |
| Absolute magnitude (MV) | -0.60 |
| Details | |
| Mass | 6 M☉ |
| Radius | 1.8 R☉ |
| Luminosity | 700 L☉ |
| Temperature | 22,000 K |
| Metallicity | ? |
| Rotation | ~200 km/s |
| Age | ? years |
| Other designations | |
Eta Ursae Majoris (η UMa / η Ursae Majoris) is a star in the constellation Ursa Major. It also has the traditional names Alkaid (or Elkeid) and Benetnash (Benetnasch).
It is known as 北斗七 (the Seventh Star of the Northern Dipper) or 搖光 (the Star of Twinkling Brilliance) in Chinese.
Alkaid is the most eastern (leftmost) star in the Big Dipper (Plough) asterism. However, unlike most stars of the Big Dipper it is not a member of the Ursa Major moving group.
Alkaid has apparent magnitude +1.9, making it the 35th brightest star in the sky. It is a young bluish-white main sequence star of spectral class B3 V. At 20,000 kelvins it is one of the hotter stars visible with the naked eye.
The name derives from القائد البنات النعش, al-qāid al-banāt an-nac meaning "The leader of the daughters of the bier". The daughters of the bier, i.e. the mourning maidens, are the three stars of the handle of the Big Dipper, Alkaid, Mizar, and Alioth.
[edit] External link
- Alkaid in Jim Kaler's Stars website
 |
This main sequence star-related article is a stub. You can help Wikipedia by expanding it. |
