Star · A0IV
Alhena
Alhena is a subgiant star of spectral type A0IV in the constellation Gemini, 109.3 light-years from the Sun.
| Other names | γ Gem · HIP 31681 |
|---|---|
| Constellation | Gemini |
| Distance | 109.3 light-years (33.5 pc) |
| Apparent magnitude | magnitude 1.93 |
| Absolute magnitude | magnitude −0.70 |
| Spectral type | A0IV |
| Surface temperature | 10,110 K |
| Luminosity | 228 L☉ |
| Radius | 4.92 R☉ |
| Mass | 4.28 M☉ (estimated) |
| Right ascension (J2000) | 6h 37m 42.7s |
| Declination (J2000) | +16° 23′ 57″ |
| Space velocity (relative to the Sun) | 15.5 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 1.93). Visible from the whole Northern Hemisphere and south to latitude 74° S. North of latitude 74° N it never sets. It stands highest at midnight in December, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1917. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 1.9 million years.
The Sun seen from there
From a planet around Alhena, the Sun would look like a star of magnitude 7.46, in the direction where our sky has the constellation Sagittarius. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.