Interstellar matter near the Pleiades. V. Observations of NaI toward 36 stars

This paper reports high-resolution, moderate to high signal-to-noise ratio observations of 23 certain Pleiades members, four possible members, and nin e nonmembers in the Na I D lines, as well as observations of 12 of the star s in the Na I ultraviolet doublet. In spite of the relative proximity of th e stars to the sun (even most of the nonmembers lie within 200 pc), the lin e profiles exhibit remarkable complexity, with up to five absorption compon ents and equally remarkable star-to-star variation. The velocity range, 2-2 0 km s(-1), conforms well to the range expected for gas deflected by the pa ssage of the cluster. The paper includes a careful discussion of uncertaint ies in the data, the most important conclusions of which are that the veloc ity scatter is consistent with that expected from random errors in the wave length calibration and that systematic errors probably are less than or sim ilar to0.1 km s(-1). Appendices detail the choice of stellar data and the p rocedure adopted for removing telluric absorption lines. Analysis follows i n a separate paper.