Star · B9II
HIP 81904
HIP 81904 is a bright giant star of spectral type B9II in the constellation Scorpius, 1,159 light-years from the Sun.
| Constellation | Scorpius |
|---|---|
| Distance | 1,159 light-years (355.4 pc) |
| Apparent magnitude | magnitude 6.05 |
| Absolute magnitude | magnitude −1.70 |
| Spectral type | B9II |
| Surface temperature | 10,850 K |
| Luminosity | 649 L☉ |
| Radius | 7.2 R☉ |
| Mass | 5.78 M☉ (estimated) |
| Right ascension (J2000) | 16h 43m 47.6s |
| Declination (J2000) | −38° 09′ 23″ |
| Space velocity (relative to the Sun) | 81.9 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 6.05). Visible from the whole Southern Hemisphere and north to latitude 52° N. South of latitude 52° S it never sets. It stands highest at midnight in May, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 867. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 21 million years.
The Sun seen from there
From a planet around HIP 81904, the Sun would look like a star of magnitude 12.58, in the direction where our sky has the constellation Perseus. It would be invisible to the naked eye.
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.