干旱区生态环境知识资源中心

We assess the potential of planet formation instigating the early formation of a photoevaporation-driven gap, up to radii larger than typical for photoevaporation alone. For our investigation we make use of hydrodynamic models of photoevaporating discs with a giant planet embedded. We find that by reducing the mass accretion flow on to the star, discs that form giant planets will be dispersed at earlier times than discs without planets by X-ray photoevaporation. By clearing the portion of the disc inner of the planet orbital radius, planet formation induced photoevaporation (PIPE) is able to produce transition discs that for a given mass accretion rate have larger holes when compared to standard X-ray photoevaporation. This constitutes a possible route for the formation of the observed class of accreting transition discs with large holes, which are otherwise difficult to explain by planet formation or photoevaporation alone. Moreover, assuming that a planet is able to filter dust completely, PIPE produces a transition disc with a large hole and may provide a mechanism to quickly shut down accretion. This process appears to be too slow, however, to explain the observed desert in the population of transition discs with large holes and low mass accretion rates.