Star · G8 V
K2-138
K2-138 is a main-sequence star of spectral type G8 V in the constellation Aquarius, 660.8 light-years from the Sun. It is orbited by 6 confirmed exoplanet(s).
| Constellation | Aquarius |
|---|---|
| Distance | 660.8 light-years (202.6 pc) |
| Apparent magnitude | magnitude 12.25 |
| Absolute magnitude | magnitude 5.72 |
| Spectral type | G8 V |
| Surface temperature | 5,360 K |
| Luminosity | 0.517 L☉ |
| Radius | 0.863 R☉ |
| Mass | 0.935 M☉ |
| Age | 2.8 billion years |
| Metallicity [Fe/H] | 0.14 |
| Right ascension (J2000) | 23h 15m 47.8s |
| Declination (J2000) | −10° 50′ 59″ |
| Space velocity (relative to the Sun) | 10.2 km/s |
In the sky
A telescope is needed to see it: its apparent magnitude is 12.25. Visible from the whole Southern Hemisphere and north to latitude 79° N. South of latitude 79° S it never sets. It stands highest at midnight in September, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1365. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 12 million years.
The Sun seen from there
From a planet around K2-138, the Sun would look like a star of magnitude 11.36, in the direction where our sky has the constellation Leo. It would be invisible to the naked eye.
Planets
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.