Astronomical evidence
HD 209458 b orbits HD 209458. The saved catalog gives an orbital period of 3.52474859 ± 3.8e-07 days. Its discovery method is recorded as radial velocity. These quantities describe the real astronomical setting behind the illustration. HD 209458 b combines a close orbit with a radius larger than Jupiter’s. A transit measures the size of the occulting disk relative to the star; stellar motion supplies complementary mass information. The two methods probe different observables, and their interpretation depends on the adopted stellar properties. The catalog radius is 15.58051 ± 0.22418 Earth radii. The mass entry is 232.0159 ± 12.7132 Earth masses. The source papers and full table retain the provenance of each parameter.
The illustrated viewpoint
The orbital hall is fictional. A giant planet’s measured radius does not provide a solid floor or imply that an ordinary exposed landscape exists at its visible cloud tops.
The orbital hall is fictional. A giant planet’s measured radius does not provide a solid floor or imply that an ordinary exposed landscape exists at its visible cloud tops. All depicted life and technology are fictional.
Catalog measurements & sources
Host: HD 209458. Snapshot: 25 September 2026. Errors, limits and source provenance are retained. Calculated values and model estimates are not direct measurements. Unknown is not zero; equilibrium temperature is not surface temperature.
| Quantity / unit | Value / reported errors | Source |
|---|---|---|
| Radius · Earth radii | 15.5805 (+0.22418 / -0.22418) | Stassun et al. 2017 |
| Mass · Earth masses | 232.016 (+12.7132 / -12.7132) | Stassun et al. 2017 |
| Density · g/cm³ | 0.362 (+0.006 / -0.006) | Southworth 2010 |
| Orbital period · days | 3.52475 (+3.8e-07 / -3.8e-07) | Stassun et al. 2017 |
| Orbital semimajor axis · AU | 0.04707 (+0.00045 / -0.00047) | Bonomo et al. 2017 |
| Eccentricity | 0 | Stassun et al. 2017 |
| Inclination · degrees | 86.71 (+0.05 / -0.05) | Stassun et al. 2017 |
| Irradiation · Earth flux | 587.098 | ExoFOP |
| Equilibrium temperature · K | 1459 (+12 / -12) | Southworth 2010 |
| Stellar effective temperature · K | 6091 (+10 / -10) | Stassun et al. 2017 |
| Stellar radius · Solar | 1.19 (+0.02 / -0.02) | Stassun et al. 2017 |
| Stellar mass · Solar | 1.23 (+0.09 / -0.09) | Stassun et al. 2017 |
| Stellar luminosity · log Solar | 0.23086 (+0.015 / -0.0123) | Barstow et al. 2017 |
| Stellar age · Gyr | 3.1 (+0.8 / -0.7) | Kokori et al. 2023 |
| Stellar metallicity · dex | 0.01 | Stassun et al. 2017 |
| Distance · pc | 48.3016 (+0.124 / -0.1234) | TICv8 |