Astronomical evidence
HR 8799 e is a young giant whose light has been directly detected separately from its host star. GRAVITY interferometry measured its position and obtained a K-band spectrum used to investigate atmospheric properties. [2] A young planet can remain bright in the infrared as internal heat escapes. That evidence motivates the warm planetary presence, while leaving the depicted cloud shapes and visible colors interpretive. Catalog radius and mass estimates retain their broad, model-dependent uncertainties. [1]
The illustrated viewpoint
Small pale-crested alien wearing an ash-grey cloak, viewed from behind in meditation. A frozen lake on an invented moon of HR 8799 e. The moon, lake, ice, atmosphere and warrior are fictional. The young giant's muted warm hue is a visible artistic translation of thermal infrared emission, not a prediction of naked-eye color. The icy terrain is not the giant's own surface. Satellite dynamics and local climate are unmodeled.
The moon, lake, ice, atmosphere and warrior are fictional. The young giant's muted warm hue is a visible artistic translation of thermal infrared emission, not a prediction of naked-eye color. The icy terrain is not the giant's own surface. Satellite dynamics and local climate are unmodeled. All beings and cultures are fictional. Apparent sizes, phases and exposure are artistic, not a calibrated sky simulation. Cosmic connection is a visual theme, not an observed biological mechanism.
Catalog measurements & sources
Host: HR 8799. 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 | 13.1145 (+1.45717 / -1.23299) | Gravity Collaboration et al. 2019 |
| Mass · Earth masses | 3178.3 (+2224.81 / -1271.32) | Gravity Collaboration et al. 2019 |
| Density · g/cm³ | 7.74 | Calculated Value |
| Orbital period · days | 20815.6 (+1128.62 / -1128.62) | Zurlo et al. 2016 |
| Orbital semimajor axis · AU | 16.4 (+2.1 / -1.1) | Gravity Collaboration et al. 2019 |
| Eccentricity | 0.15 (+0.08 / -0.08) | Gravity Collaboration et al. 2019 |
| Inclination · degrees | 25 (+8 / -8) | Gravity Collaboration et al. 2019 |
| Irradiation · Earth flux | 0.0201 (+0.004 / -0.004) | Calculated Value |
| Equilibrium temperature · K | 1150 (+50 / -50) | Gravity Collaboration et al. 2019 |
| Stellar effective temperature · K | 7400 | Gravity Collaboration et al. 2019 |
| Stellar radius · Solar | 1.49338 (+0.049341 / -0.050935) | Konopacky et al. 2016 |
| Stellar mass · Solar | 1.51 (+0.038 / -0.024) | Zurlo et al. 2016 |
| Stellar luminosity · log Solar | 0.73347 (+0.01645 / -0.01535) | Konopacky et al. 2016 |
| Stellar age · Gyr | 0.03 | Gravity Collaboration et al. 2019 |
| Stellar metallicity · dex | -0.5 | Gravity Collaboration et al. 2019 |
| Distance · pc | 41.2441 (+0.1515 / -0.1505) | TICv8 |