We think we know how stars live and die, but our picture of how stars form to begin with is incomplete. Although astronomers have discovered more than 1000 planets in other solar systems, we do not really know what conditions actually produce life.
Over the last twelve years the continuing discovery and increasingly accurate characterization of brown dwarfs and extrasolar giant planets (EGPs) have created a new frontier in stellar and planetary astronomy. The development of accurate spectral diagnostics and the refinement of the theoretical models to describe these objects are among the most important challenges for the future.
Brown dwarfs are Janus-faced objects that straddle the mass range between stars and planets: sharing many characteristics with both but classifiable as neither, they offer fundamental insights into formation and properties in both the stellar and planetary regimes.
Using a radiative transfer and climate models developed at the CfA and elsewhere, we model Earth and extrasolar planet atmospheres and their spectra to identify spectral fingerprints which may characterize these worlds.