Astronomical evidence
55 Cnc e completes an orbit in about 0.737 days. The saved composite catalog gives a radius of 1.875 ± 0.029 Earth radii and a mass of 7.99 (+0.32/−0.33) Earth masses. These are the values retained for consistency with the atlas snapshot; a source paper can adopt a different parameter solution. The full companion table preserves the source of each measurement. [1] Hu and colleagues used JWST observations of thermal emission between 4 and 12 micrometres to investigate the planet’s atmosphere. Their analysis favors a volatile atmosphere containing carbon-bearing gases, rather than a tenuous layer made only of vaporized rock. Carbon monoxide and carbon dioxide are plausible contributors. This interpretation comes from a spectrum, not a photograph of a molten hemisphere. [2] A magma ocean could supply gases and help sustain a secondary atmosphere. That physical possibility motivates the incandescent landscape, but the distribution of crust, melt and clouds remains unknown. Heating, atmospheric circulation and surface emission all affect the light an observer receives. The artwork therefore makes a clear distinction between spectral evidence and imagined geography. [2]
The illustrated viewpoint
Humanoid / veiled ivory and malachite regent. A fictional shielded orbital enclosure above 55 Cnc e. The molten hemisphere, crustal islands and atmospheric rim are an interpretation, not a resolved map. The atmosphere’s exact composition remains model dependent. Window filtering, radiation protection and the humanoid are fictional; exposed life on this scorching world is not implied.
The molten hemisphere, crustal islands and atmospheric rim are an interpretation, not a resolved map. The atmosphere’s exact composition remains model dependent. Window filtering, radiation protection and the humanoid are fictional; exposed life on this scorching world is not implied. All beings, civilizations and technology are fictional. No motives, moral alignment or character history is asserted.
Catalog measurements & sources
Host: 55 Cnc. 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 | 1.875 (+0.029 / -0.029) | Bourrier et al. 2018 |
| Mass · Earth masses | 7.99 (+0.32 / -0.33) | Bourrier et al. 2018 |
| Density · g/cm³ | 6.66 (+0.43 / -0.4) | Bourrier et al. 2018 |
| Orbital period · days | 0.736547 (+1.3e-06 / -1.4e-06) | Bourrier et al. 2018 |
| Orbital semimajor axis · AU | 0.01544 (+5e-05 / -5e-05) | Bourrier et al. 2018 |
| Eccentricity | 0.05 (+0.03 / -0.03) | Bourrier et al. 2018 |
| Inclination · degrees | 83.59 (+0.47 / -0.44) | Bourrier et al. 2018 |
| Irradiation · Earth flux | 2657.83 | ExoFOP |
| Equilibrium temperature · K | 1958 (+15 / -15) | Demory et al. 2011 |
| Stellar effective temperature · K | 5172 (+18 / -18) | Bourrier et al. 2018 |
| Stellar radius · Solar | 0.943 (+0.01 / -0.01) | Bourrier et al. 2018 |
| Stellar mass · Solar | 0.905 (+0.015 / -0.015) | Bourrier et al. 2018 |
| Stellar luminosity · log Solar | -0.19695 (+0.0125 / -0.01039) | Knapp et al. 2020 |
| Stellar age · Gyr | 5.5 (+2.5 / -2.5) | Marcy et al. 2002 |
| Stellar metallicity · dex | 0.35 (+0.1 / -0.1) | Bourrier et al. 2018 |
| Distance · pc | 12.5855 (+0.0124 / -0.0123) | TICv8 |