Star · K2 II
BD+20 2457
BD+20 2457 is a supergiant star of spectral type K2 II in the constellation Leo, 4,805 light-years from the Sun. It is orbited by 2 confirmed exoplanet(s).
| Constellation | Leo |
|---|---|
| Distance | 4,805 light-years (1,473 pc) |
| Apparent magnitude | magnitude 9.88 |
| Absolute magnitude | magnitude −0.96 |
| Spectral type | K2 II |
| Surface temperature | 4,140 K |
| Luminosity | 1,480 L☉ |
| Radius | 49 R☉ |
| Mass | 2.8 M☉ |
| Metallicity [Fe/H] | -1.00 |
| Right ascension (J2000) | 10h 16m 44.9s |
| Declination (J2000) | +19° 53′ 29″ |
| Space velocity (relative to the Sun) | 357.7 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 9.88. 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 February, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 4,805 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 85 million years.
The Sun seen from there
From a planet around BD+20 2457, the Sun would look like a star of magnitude 15.67, in the direction where our sky has the constellation Aquarius. It would be invisible to the naked eye.
Planets
- BD+20 2457 b 380-day orbit · 12.1 R⊕
- BD+20 2457 c 622-day orbit · 12.4 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.