摘要：Reference star differential imaging (RDI) is a powerful strategy for high-contrast imaging. Using example observations taken with the vortex coronagraph mode of Keck/NIRC2 in L′ band, we demonstrate that RDI provides improved sensitivity to point sources at small angular separations compared to angular differential imaging (ADI). Applying RDI to images of the low-mass stellar companions HIP79124C (192mas separation, ΔL′=4.01) and HIP78233B (141mas separation, ΔL′=4.78), the latter a first imaging detection, increases the significance of their detections by up to a factor of 5 with respect to ADI. We compare methods for reference frame selection and find that pre-selection of frames improves detection significance of point sources by up to a factor of 3. In addition, we use observations of the circumstellar disks around MWC758 and 2MASSJ16042165−2130284 to show that RDI allows for accurate mapping of scattered light distributions without self-subtraction artifacts.
关键词：planets and satellites: detection;protoplanetary disks;stars: imaging;stars: individual (MWC 758, 2MASS J16042165−2130284);techniques: high angular resolution
