Star · M3
GJ 4240
GJ 4240 is a main-sequence star of spectral type M3 in the constellation Pegasus, 72.3 light-years from the Sun.
| Constellation | Pegasus |
|---|---|
| Distance | 72.3 light-years (22.2 pc) |
| Apparent magnitude | magnitude 12.90 |
| Absolute magnitude | magnitude 11.17 |
| Spectral type | M3 |
| Surface temperature | 3,680 K |
| Luminosity | 0.0126 L☉ |
| Radius | 0.277 R☉ |
| Mass | 0.283 M☉ (estimated) |
| Right ascension (J2000) | 21h 56m 37.9s |
| Declination (J2000) | +19° 46′ 10″ |
| Space velocity (relative to the Sun) | 51.3 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 12.90. Visible from the whole Northern Hemisphere and south to latitude 70° S. North of latitude 70° N it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1954. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 1.3 million years.
The Sun seen from there
From a planet around GJ 4240, the Sun would look like a star of magnitude 6.56, in the direction where our sky has the constellation Hydra. It would be invisible to the naked eye.
Neighbours
Its nearest neighbours in the catalogue (within 20 light-years):
- HIP 108028 3.96 light-years
- GJ 4218 4.14 light-years
- GJ 9784 9.64 light-years
- Gl 857.1B 9.66 light-years
- Gl 857.1A 9.69 light-years
- WISEA J221841.38+143003.4 9.95 light-years
- 2MASS J21371044+1450475 9.97 light-years
- GJ 4264 10.1 light-years
Position, brightness and colour from the HYG / AT-HYG catalogue; temperature, luminosity, radius and mass are approximate values computed from these observations.