Star · F8I
Sadr
Sadr is a supergiant star of spectral type F8I in the constellation Cygnus, 1,832 light-years from the Sun.
| Other names | γ Cyg · HIP 100453 |
|---|---|
| Constellation | Cygnus |
| Distance | 1,832 light-years (561.8 pc) |
| Apparent magnitude | magnitude 2.23 |
| Absolute magnitude | magnitude −6.52 |
| Spectral type | F8I |
| Surface temperature | 5,700 K |
| Luminosity | 38,200 L☉ |
| Radius | 201 R☉ |
| Mass | 18.5 M☉ (estimated) |
| Right ascension (J2000) | 20h 22m 13.7s |
| Declination (J2000) | +40° 15′ 24″ |
| Space velocity (relative to the Sun) | 9.0 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 2.23). Visible from the whole Northern Hemisphere and south to latitude 50° S. North of latitude 50° N 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 194. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 33 million years.
The Sun seen from there
From a planet around Sadr, the Sun would look like a star of magnitude 13.58, in the direction where our sky has the constellation Puppis. 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.