2003ApJS..148..487W

This paper seeks a comprehensive interpretation of new data on Na I absorption toward stars in and near the Pleiades, together with existing visible and infrared data on the distribution of dust and with radio data on H I and CO in the cluster vicinity. The use of dust and gas morphology to constrain tangential motions in connection with the measured radial velocities yields estimates for the space motion of gas near the Pleiades. Much of the kinematic complexity in the interstellar absorption toward the Pleiades, including the presence of strongly blueshifted components that arise in shocked gas, finds explanation in the interaction between the cluster and foreground gas with V_r(LSR)~7 km/s associated with the Taurus dust clouds. Taurus gas, however, cannot readily account for an absorption component having V_r(LSR)~10 km/s with a wide, but not continuous distribution and 21 cm emission from gas in the cluster having V_r(LSR)~0 km/s associated with east-west dust filaments. Successive hypotheses for the origin of these additional features include Taurus gas at a higher velocity than the pervasive foreground component, additional gas at a radial velocity intermediate between that of the Taurus component and the cluster, and a cloud having V_r(LSR)~10 km/s approaching the Pleiades from the west. A satisfactory account of the full complexity of the interstellar medium near the Pleiades requires the last feature and the Taurus gas, both interacting with the Pleiades and also with each other.