Star · B2V
Nunki
Nunki is a main-sequence star of spectral type B2V in the constellation Sagittarius, 227.8 light-years from the Sun.
| Other names | σ Sgr · HIP 92855 |
|---|---|
| Constellation | Sagittarius |
| Distance | 227.8 light-years (69.8 pc) |
| Apparent magnitude | magnitude 2.05 |
| Absolute magnitude | magnitude −2.17 |
| Spectral type | B2V |
| Surface temperature | 12,180 K |
| Luminosity | 1,240 L☉ |
| Radius | 7.91 R☉ |
| Mass | 6.95 M☉ (estimated) |
| Right ascension (J2000) | 18h 55m 15.9s |
| Declination (J2000) | −26° 17′ 48″ |
| Space velocity (relative to the Sun) | 21.6 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 2.05). Visible from the whole Southern Hemisphere and north to latitude 64° N. South of latitude 64° S it never sets. It stands highest at midnight in July, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1798. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 4.0 million years.
The Sun seen from there
From a planet around Nunki, the Sun would look like a star of magnitude 9.05, in the direction where our sky has the constellation Gemini. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 92104 11.9 light-years
- HIP 93375 17.8 light-years
- 30 Sgr 19.0 light-years
- HIP 91991 19.3 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.