Star · K0
Gl 640
Gl 640 is a main-sequence star of spectral type K0 in the constellation Hercules, 89.4 light-years from the Sun.
| Other names | HIP 82389 |
|---|---|
| Constellation | Hercules |
| Distance | 89.4 light-years (27.4 pc) |
| Apparent magnitude | magnitude 8.85 |
| Absolute magnitude | magnitude 6.66 |
| Spectral type | K0 |
| Surface temperature | 4,700 K |
| Luminosity | 0.299 L☉ |
| Radius | 0.826 R☉ |
| Mass | 0.739 M☉ (estimated) |
| Right ascension (J2000) | 16h 50m 05.3s |
| Declination (J2000) | +18° 54′ 01″ |
| Space velocity (relative to the Sun) | 12.5 km/s |
In the sky
Too faint for the naked eye (magnitude 8.85); binoculars will find it. Visible from the whole Northern Hemisphere and south to latitude 71° S. North of latitude 71° N it never sets. It stands highest at midnight in June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1937. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 1.6 million years.
The Sun seen from there
From a planet around Gl 640, the Sun would look like a star of magnitude 7.02, 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 83343 7.70 light-years
- WISEA J162852.64+160421.0 9.07 light-years
- GJ 3980 9.32 light-years
- HIP 80539 10.1 light-years
- PSO J246.4222+15.4698 10.6 light-years
- SDSS J162603.03+211313.0 11.9 light-years
- 2MASSI J1711457+223204 13.2 light-years
- κ Oph 15.1 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.