An Imaging Survey for Extrasolar Planets around 45 Close, Young Stars with SDI at the VLT and MMT

We present the results of a survey of 45 young (.250 Myr), close (.50 pc) stars with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT for the direct detection of extrasolar planets. As part of the survey, we observed 54 objects total, of which 45 were close, young stars, 2 were somewhat more distant (<150 pc), very young (≤10 Myr) stars, 3 were stars with known radial velocity planets, and 4 were older, very nearby (≤20 pc) solar analogues. Our SDI devices use a double Wollaston prism and a quad filter to take images simultaneously at 3 wavelengths surrounding the 1.62 μm methane absorption bandhead found in the spectrum of cool brown dwarfs and gas giant planets. By performing a difference of adaptive optics corrected images in these filters, speckle noise from the primary star can be significantly attenuated, resulting in photon (and flat-field) noise limited data. In our VLT data, we achieved H band contrasts & 10 mag (5σ) at a separation of 0.5” from the primary star on 45% of our targets and H band contrasts of & 9 mag at a separation of 0.5” on based on observations made with the MMT and the ESO VLT at Paranal Observatory under programme ID’s 074.C-0548, 074.C-0549, and 076.C-0094