Star · F0IV
23 UMa
23 UMa is a subgiant star of spectral type F0IV in the constellation Ursa Major, 77.5 light-years from the Sun.
| Other names | GJ 3559 · HIP 46733 |
|---|---|
| Constellation | Ursa Major |
| Distance | 77.5 light-years (23.8 pc) |
| Apparent magnitude | magnitude 3.65 |
| Absolute magnitude | magnitude 1.77 |
| Spectral type | F0IV |
| Surface temperature | 7,100 K |
| Luminosity | 16.7 L☉ |
| Radius | 2.7 R☉ |
| Mass | 2.03 M☉ (estimated) |
| Right ascension (J2000) | 9h 31m 31.6s |
| Declination (J2000) | +63° 03′ 43″ |
| Space velocity (relative to the Sun) | 12.6 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 3.65). Visible from the whole Northern Hemisphere and south to latitude 27° S. North of latitude 27° N it never sets. It stands highest at midnight in February, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1949. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 1.4 million years.
The Sun seen from there
From a planet around 23 UMa, the Sun would look like a star of magnitude 6.71, in the direction where our sky has the constellation Indus. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- SDSSp J092615.38+584720.9 6.26 light-years
- 2MASS J08593854+6341355 7.43 light-years
- WISEPA J101905.63+652954.2 7.77 light-years
- 2MASS J09054654+5623117 10.3 light-years
- GJ 3606 10.5 light-years
- WISEA J090258.99+670833.1 11.1 light-years
- GJ 3509 11.6 light-years
- 16 UMa 11.9 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.