Star · M3
τ⁴ Eri
τ⁴ Eri is a supergiant star of spectral type M3 in the constellation Eridanus, 307.3 light-years from the Sun.
| Other names | HIP 15474 |
|---|---|
| Constellation | Eridanus |
| Distance | 307.3 light-years (94.2 pc) |
| Apparent magnitude | magnitude 3.70 |
| Absolute magnitude | magnitude −1.17 |
| Spectral type | M3 |
| Surface temperature | 3,630 K |
| Luminosity | 1,170 L☉ |
| Radius | 86.5 R☉ |
| Mass | 6.84 M☉ (estimated) |
| Right ascension (J2000) | 3h 19m 31.0s |
| Declination (J2000) | −21° 45′ 28″ |
| Space velocity (relative to the Sun) | 50.3 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 3.70). Visible from the whole Southern Hemisphere and north to latitude 68° N. South of latitude 68° S it never sets. It stands highest at midnight in November, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1719. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 5.5 million years.
The Sun seen from there
From a planet around τ⁴ Eri, the Sun would look like a star of magnitude 9.70, in the direction where our sky has the constellation Serpens. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 15660 13.3 light-years
- HIP 16274 14.8 light-years
- HIP 14498 16.4 light-years
- HIP 15016 19.6 light-years
- HIP 15418 19.8 light-years
- HIP 15561 19.8 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.