An improbable solution to the underluminosity of 2M1207B: A hot protoplanet collision afterglow

We introduce an alternative hypothesis to explain the very low luminosity of the cool ( L- type) companion to the similar to 25 M-Jup, similar to 8 Myr old brown dwarf 2M1207A. Recently, Mohanty et al. found that effective temperature estimates for 2M1207B (1600 +/- 100 K) are grossly inconsistent with its lying on the same isochrone as the primary, being a factor of similar to 10 underluminous at all bands between I ( 0.8 mu m) and L' (3.6 mu m). Mohanty et al. explain this discrepancy by suggesting that 2M1207B is an 8 M-Jup object surrounded by an edge- on disk comprised of large dust grains producing 2.5 mag of achromatic extinction. We offer an alternative explanation: the apparent flux reflects the actual source luminosity. Given the temperature, we infer a small radius (similar to 49,000 km), and for a range of plausible densities, we estimate a mass