Star · G5IV
21 Cet
21 Cet is a subgiant star of spectral type G5IV in the constellation Cetus, 411.6 light-years from the Sun.
| Other names | HIP 4257 |
|---|---|
| Constellation | Cetus |
| Distance | 411.6 light-years (126.2 pc) |
| Apparent magnitude | magnitude 6.15 |
| Absolute magnitude | magnitude 0.64 |
| Spectral type | G5IV |
| Surface temperature | 4,970 K |
| Luminosity | 65.9 L☉ |
| Radius | 11 R☉ |
| Mass | 3.01 M☉ (estimated) |
| Right ascension (J2000) | 0h 54m 17.6s |
| Declination (J2000) | −8° 44′ 26″ |
| Space velocity (relative to the Sun) | 55.6 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 6.15). Visible from the whole Southern Hemisphere and north to latitude 81° N. It stands highest at midnight in October, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1614. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 7.3 million years.
The Sun seen from there
From a planet around 21 Cet, the Sun would look like a star of magnitude 10.34, in the direction where our sky has the constellation Virgo. It would be invisible to the naked eye.
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.