Star · K3 III
HD 240210
HD 240210 is a supergiant star of spectral type K3 III in the constellation Cassiopeia, 1,236 light-years from the Sun. It is orbited by 1 confirmed exoplanet(s).
| Constellation | Cassiopeia |
|---|---|
| Distance | 1,236 light-years (379.1 pc) |
| Apparent magnitude | magnitude 8.47 |
| Absolute magnitude | magnitude 0.58 |
| Spectral type | K3 III |
| Surface temperature | 4,300 K |
| Luminosity | 35.5 L☉ |
| Radius | 25.5 R☉ |
| Mass | 0.82 M☉ |
| Age | 5.1 billion years |
| Metallicity [Fe/H] | -0.18 |
| Right ascension (J2000) | 23h 10m 29.2s |
| Declination (J2000) | +57° 01′ 46″ |
| Space velocity (relative to the Sun) | 36.6 km/s |
In the sky
Too faint for the naked eye (magnitude 8.47); binoculars will find it. Visible from the whole Northern Hemisphere and south to latitude 33° S. North of latitude 33° N 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 790. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 22 million years.
The Sun seen from there
From a planet around HD 240210, the Sun would look like a star of magnitude 12.72, in the direction where our sky has the constellation Centaurus. It would be invisible to the naked eye.
Planets
- HD 240210 b 502-day orbit · 12.8 R⊕
Stellar parameters from the NASA Exoplanet Archive; position and brightness from the HYG / AT-HYG catalogue.