High-resolution survey for planetary companions to young stars in the Taurus molecular cloud.

Direct imaging in the infrared at the diffraction limit of large telescopes is a unique probe of the properties of young planetary systems. We survey 55 single class I and class II stars in Taurus in the L ' filter using natural and laser guide star adaptive optics and the near-infrared camera (NIRC2) of the Keck II telescope, in order to search for planetary-mass companions. We use both reference star differential imaging and kernel phase techniques, achieving typical 5σ contrasts of ∼6 mag at separations of 0.2 arcsec and ∼8 mag beyond 0.5 arcsec. Although, we do not detect any new faint companions, we constrain the frequency of wide separation massive planets, such as HR 8799 analogues. We find that, assuming hot-start models and a planet distribution with power-law mass and semimajor axis indices of −0.5 and −1, respectively, less than 20 per cent of our target stars host planets with masses >2  M _J at separations >10 au. [ABSTRACT FROM AUTHOR]