HD 189733 planetary system
HD 189733 is an orange main-sequence star of spectral type K2 V approximately 64.5 light-years from Earth (19.76 parsecs). It hosts 1 confirmed exoplanet. 1 planet transits the host star from our line of sight, allowing direct measurements of size and atmosphere.
Host star
- Name
- HD 189733
- Spectral type
- K2 V
- Effective temperature
- 5,052 K
- Mass
- 0.79 M☉ (solar masses)
- Radius
- 0.75 R☉ (solar radii)
- Distance
- 19.76 pc (64.5 ly)
- Hipparcos catalog
- HIP 98505
Confirmed planets (1)
| Planet | Class | Mass (M⊕) | Radius (R⊕) | Period (d) | Distance (AU) | Eq. temp (K) | Discovered |
|---|---|---|---|---|---|---|---|
| HD 189733 b | Neptune-like | 359.15 | 12.67 | 2.22 | 0.0313 | 1,209 | 2005 |
The planets in detail
HD 189733 b is a Neptune-like world with about 12.67 Earth radii and 359.15 Earth masses. It orbits HD 189733 at 0.0313 AU with a 2.2-day year, soaked in over 356× Earth's stellar flux, and an extreme equilibrium temperature exceeding 1209 K. The planet transits its host star, which is how its radius and (when combined with mass) bulk density are pinned down. It was confirmed in 2005 via radial velocity (Doppler) measurements.
Discovery
The single planet in the HD 189733 system was confirmed in 2005 using radial velocity (Doppler) measurements. Detection facilities: Haute-Provence Observatory.
Observing from Earth
Exoplanets cannot be resolved visually with amateur telescopes — the host star's glare is overwhelming and even space-based direct imaging requires sophisticated coronagraphs. What you can observe is the host star itself at right ascension 300.1821°, declination 22.7098°. Because 1 planet transits from our perspective, advanced amateurs with photometric setups can sometimes detect the resulting brightness dips. Use the 3D orrery above to inspect orbital geometry, planetary scale, and the habitable-zone overlay — the orbits are computed from the published Keplerian elements and animate at user-controlled time rates.
