Star · K2 III
τ Gem
τ Gem is a giant star of spectral type K2 III in the constellation Gemini, 391.7 light-years from the Sun. It is orbited by 1 confirmed exoplanet(s).
| Other names | tau Gem · HIP 34693 |
|---|---|
| Constellation | Gemini |
| Distance | 391.7 light-years (120.1 pc) |
| Apparent magnitude | magnitude 4.41 |
| Absolute magnitude | magnitude −0.99 |
| Spectral type | K2 III |
| Surface temperature | 4,390 K |
| Luminosity | 330 L☉ |
| Radius | 26.8 R☉ |
| Mass | 2.3 M☉ |
| Age | 1.2 billion years |
| Metallicity [Fe/H] | 0.14 |
| Right ascension (J2000) | 7h 11m 08.4s |
| Declination (J2000) | +30° 14′ 43″ |
| Space velocity (relative to the Sun) | 39.3 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 4.41). Visible from the whole Northern Hemisphere and south to latitude 60° S. North of latitude 60° N it never sets. It stands highest at midnight in January, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1634. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 6.9 million years.
The Sun seen from there
From a planet around τ Gem, the Sun would look like a star of magnitude 10.23, in the direction where our sky has the constellation Sagittarius. It would be invisible to the naked eye.
Planets
- tau Gem b 306-day orbit · 12.1 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.