Star · B3V
Alkaid
Alkaid is a main-sequence star of spectral type B3V in the constellation Ursa Major, 103.9 light-years from the Sun.
| Other names | η UMa · HIP 67301 |
|---|---|
| Constellation | Ursa Major |
| Distance | 103.9 light-years (31.9 pc) |
| Apparent magnitude | magnitude 1.85 |
| Absolute magnitude | magnitude −0.67 |
| Spectral type | B3V |
| Surface temperature | 11,560 K |
| Luminosity | 280 L☉ |
| Radius | 4.18 R☉ |
| Mass | 4.54 M☉ (estimated) |
| Right ascension (J2000) | 13h 47m 32.4s |
| Declination (J2000) | +49° 18′ 48″ |
| Space velocity (relative to the Sun) | 22.8 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 1.85). Visible from the whole Northern Hemisphere and south to latitude 41° S. North of latitude 41° N it never sets. It stands highest at midnight in April, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1922. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 1.8 million years.
The Sun seen from there
From a planet around Alkaid, the Sun would look like a star of magnitude 7.35, in the direction where our sky has the constellation Phoenix. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 68403 9.43 light-years
- DE CVn 10.1 light-years
- Xuange 11.1 light-years
- SDSS J135923.99+472843.2 11.4 light-years
- ι Boo 11.6 light-years
- GJ 9474B 11.9 light-years
- HIP 66110 12.0 light-years
- 2MASS J13373116+4938367 14.2 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.