Detectability of Red-Edge Shifted Vegetation on M-star Terrestrial Planets

We have explored the detectability of exo-vegetation on the surface of a terrestrial planet orbiting a M-star. The exo-vegetation is responsible for producing a red-edge like signature that is red-shifted with respect to the Earth vegetation red-edge. The red-shift was estimated using a model of leaf optical properties spectra (Jacquemoud, 1990) combined with a three photon photosynthetic scheme calculated by Wolstencroft and Raven (2002) for possible exo-vegetation growing on a M-star planet. To study the detectability of this surface biosignature on a M-star terrestrial planet, we have used the 3-D model developed by Tinetti et al. (2005) for the case of the Earth. This model can generate disk-averaged spectra and broad-band integrated fluxes, useful to future terrestrial planet exploration missions, such as NASA Terrestrial Planet Finder-Coronograph. Input to this model, were the atmospheric profiles and cloud distributions predicted by Joshi (2003) for a synchronous planet orbiting a M-star and the distinctive surface reflectance of the exo-vegetation. Finally, we discuss here the sensitivity of Earth tuned indicator of vegetation, such as Normalized Difference Vegetation Index (NDVI), to these new exotic scenarios.