2014MNRAS.445.3315N

The high rate of planet detection among solar-type stars argues that planet formation is common. It is also generally assumed that planets form in protoplanetary discs like those observed in nearby star-forming regions. On what time-scale does the transformation from discs to planets occur? Here, we show that current inventories of planets and protoplanetary discs are sensitive enough to place basic constraints on the time-scale and efficiency of the planet formation process. A comparison of planet detection statistics and the measured solid reservoirs in T Tauri discs suggests that planet formation is likely already underway at the few Myr age of the discs in Taurus-Auriga, with a large fraction of solids having been converted into large objects with low millimetre opacity and/or sequestered at small disc radii where they are difficult to detect at millimetre wavelengths.