Extreme weather variability on hot rocky exoplanet 55 Cancri e explained by magma temperature-cloud feedback

Area of Science:

• Exoplanetary Science
• Atmospheric Physics
• Planetary Geology

Background:

• The exoplanet 55 Cancri e exhibits significant, unexplained brightness variability in visible and infrared light.
• Subweekly fluctuations in its mid-infrared brightness temperature reach approximately 1,400 K.

Purpose of the Study:

• To propose and investigate a magma temperature-cloud feedback mechanism as an explanation for the observed brightness variability of 55 Cancri e.
• To model the potential impact of atmospheric and surface processes on exoplanet observations.

Main Methods:

• Development of a simple model to simulate a magma temperature-cloud feedback loop.
• Analysis of how stellar radiation, silicate vapor condensation, and atmospheric transport influence surface temperature and cloud cover.
• Comparison of model predictions with observational data from 55 Cancri e, including secondary eclipse depths and phase curves.

Main Results:

• The proposed feedback mechanism can reproduce the observed infrared brightness variability of 55 Cancri e.
• Brightness oscillations at different wavelengths can occur out of phase, aligning with recent James Webb Space Telescope data.
• Time-varying, non-uniform cloud cover can explain observed phase curve variations.

Conclusions:

• A magma temperature-cloud feedback is a plausible explanation for the dynamic atmosphere and surface of 55 Cancri e.
• This mechanism offers insights into exoplanetary volatile cycles and atmospheric dynamics.
• Further observations are proposed to validate this feedback model on 55 Cancri e.