Star · F2III
39 Her
39 Her is a giant star of spectral type F2III in the constellation Hercules, 140.7 light-years from the Sun.
| Other names | HIP 81729 |
|---|---|
| Constellation | Hercules |
| Distance | 140.7 light-years (43.1 pc) |
| Apparent magnitude | magnitude 5.92 |
| Absolute magnitude | magnitude 2.75 |
| Spectral type | F2III |
| Surface temperature | 6,870 K |
| Luminosity | 6.77 L☉ |
| Radius | 1.84 R☉ |
| Mass | 1.61 M☉ (estimated) |
| Right ascension (J2000) | 16h 41m 36.7s |
| Declination (J2000) | +26° 55′ 01″ |
| Space velocity (relative to the Sun) | 15.1 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 5.92). Visible from the whole Northern Hemisphere and south to latitude 63° S. North of latitude 63° N 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 1885. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 2.5 million years.
The Sun seen from there
From a planet around 39 Her, the Sun would look like a star of magnitude 8.00, in the direction where our sky has the constellation Eridanus. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 80876 6.24 light-years
- HIP 81378 10.9 light-years
- 2MASSI J1656188+283506 11.0 light-years
- HIP 83274 11.5 light-years
- ULAS J161710.39+235031.4 15.7 light-years
- Kornephoros 16.9 light-years
- HIP 79327 17.5 light-years
- Gl 630 17.7 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.