Astronomical evidence
WASP-17 b is an inflated giant in a roughly 3.74-day orbit. Its large atmospheric extent makes it a useful target for transmission spectroscopy: during transit, a small portion of the star’s light passes through the planet’s atmospheric edge. Absorption and scattering change the apparent transit depth with wavelength. Webb’s Mid-Infrared Instrument measured a feature near 8.6 micrometers that Grant and colleagues interpreted as evidence for quartz nanocrystals. This links a familiar mineral to an unfamiliar setting: tiny suspended particles in a hot giant’s upper atmosphere. The interpretation comes from comparing spectra with atmospheric and cloud models. It does not show individual crystals, establish a landscape of quartz pillars or require particles lifted from exposed rock. The cloud particles discussed in the study are vastly smaller than the decorative crystalline forms commonly used in science-fiction art.
The illustrated viewpoint
Six-vane spiral shell organism in a still, inward-folded meditative pose. A fictional shielded orbital conservatory overlooking a hot gas giant. The scene therefore uses a fictional protected observatory. Its foreground mineral surfaces belong to that invented structure; the cloud globe’s visible colors and texture are an artistic rendering of an unresolved atmosphere.
The scene therefore uses a fictional protected observatory. Its foreground mineral surfaces belong to that invented structure; the cloud globe’s visible colors and texture are an artistic rendering of an unresolved atmosphere. All depicted life is fictional. The visual connection to the cosmos is an artistic theme, not a claimed biological mechanism.
Catalog measurements & sources
Host: WASP-17. 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 | 20.9608 (+2.69016 / -2.69016) | Stassun et al. 2017 |
| Mass · Earth masses | 247.907 (+73.1009 / -73.1009) | Stassun et al. 2017 |
| Density · g/cm³ | 0.082 (+0.0064 / -0.0064) | Southworth et al. 2012 |
| Orbital period · days | 3.73543 (+8e-06 / -8e-06) | Stassun et al. 2017 |
| Orbital semimajor axis · AU | 0.0515 (+0.00034 / -0.00034) | Anderson et al. 2011 |
| Eccentricity | 0 | Stassun et al. 2017 |
| Inclination · degrees | 86.63 (+0.42 / -0.42) | Stassun et al. 2017 |
| Irradiation · Earth flux | 1292.19 | ExoFOP |
| Equilibrium temperature · K | 1755 (+28 / -28) | Southworth et al. 2012 |
| Stellar effective temperature · K | 6550 (+100 / -100) | Stassun et al. 2017 |
| Stellar radius · Solar | 1.49 (+0.19 / -0.19) | Stassun et al. 2017 |
| Stellar mass · Solar | 2.28 (+0.99 / -0.99) | Stassun et al. 2017 |
| Stellar luminosity · log Solar | 0.61272 (+0.0319 / -0.03196) | Panek et al. 2023 |
| Stellar age · Gyr | 2.65 (+0.25 / -0.25) | Bonomo et al. 2017 |
| Stellar metallicity · dex | -0.25 | Stassun et al. 2017 |
| Distance · pc | 405.908 (+8.779 / -8.421) | TICv8 |