Star · F2V
21 Mon
21 Mon is a main-sequence star of spectral type F2V in the constellation Monoceros, 285.3 light-years from the Sun.
| Other names | HIP 34724 |
|---|---|
| Constellation | Monoceros |
| Distance | 285.3 light-years (87.5 pc) |
| Apparent magnitude | magnitude 5.44 |
| Absolute magnitude | magnitude 0.73 |
| Spectral type | F2V |
| Surface temperature | 7,400 K |
| Luminosity | 44 L☉ |
| Radius | 4.04 R☉ |
| Mass | 2.68 M☉ (estimated) |
| Right ascension (J2000) | 7h 11m 23.6s |
| Declination (J2000) | −0° 18′ 07″ |
| Space velocity (relative to the Sun) | 44.9 km/s |
In the sky
Visible to the naked eye under a dark sky (apparent magnitude 5.44). Visible from the whole Southern Hemisphere and north to latitude 90° N. 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 1741. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 5.1 million years.
The Sun seen from there
From a planet around 21 Mon, the Sun would look like a star of magnitude 9.54, in the direction where our sky has the constellation Aquila. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 35098 11.3 light-years
- HIP 33819 13.0 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.