A Multi-Epoch Reflected-Light Search for Wildfires and Forest Recovery on Terrestrial Exoplanets

Kurzfassung

I propose a differential, multi-epoch search for catastrophic wildfire and subsequent ecosystem recovery on forest-dominated terrestrial exoplanets. The strongest observable is not a small change in atmospheric CO2 measured in transmission, but a temporally ordered combination in directly imaged reflected light: rapid smoke and CO enhancement, a persistent wavelength-dependent albedo change at a fixed rotational phase, weakening of a pre-existing photosynthetic reflectance edge, and gradual restoration of the surface spectrum. Terrestrial Landsat measurements show that severe fires can change local NIR and SWIR reflectance by about 0.1. In a linear areal-mixing approximation, a one-percent projected burned fraction therefore produces disk-integrated single-band albedo perturbations of order 10−3. A future kilometer-class filled-aperture observatory could perform the full time-domain experiment.