Star · K3 III
HD 81817
HD 81817 is a giant star of spectral type K3 III in the constellation Draco, 920.8 light-years from the Sun. It is orbited by 2 confirmed exoplanet(s).
| Other names | HIP 47193 |
|---|---|
| Constellation | Draco |
| Distance | 920.8 light-years (282.3 pc) |
| Apparent magnitude | magnitude 4.28 |
| Absolute magnitude | magnitude −2.97 |
| Spectral type | K3 III |
| Surface temperature | 4,140 K |
| Luminosity | 1,820 L☉ |
| Radius | 83.8 R☉ |
| Mass | 4.3 M☉ |
| Age | 0.2 billion years |
| Metallicity [Fe/H] | -0.17 |
| Right ascension (J2000) | 9h 37m 05.3s |
| Declination (J2000) | +81° 19′ 35″ |
| Space velocity (relative to the Sun) | 31.6 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 4.28). Visible from the whole Northern Hemisphere and south to latitude 9° S. North of latitude 9° N it never sets.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1105. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 16 million years.
The Sun seen from there
From a planet around HD 81817, the Sun would look like a star of magnitude 12.08, in the direction where our sky has the constellation Octans. It would be invisible to the naked eye.
Planets
- HD 81817 c 623-day orbit · 12 R⊕
- HD 81817 b 1,020-day orbit · 12 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.