High-resolution observations of interstellar Na I towards HD 174632

High resolution observations of interstellar Na I towards the relatively nearby (180 pc) and lightly reddened [E(B-V)=0.12] B8V star HD 174632 are presented. There are two distinct interstellar cloud components in this line-of-sight, with heliocentric velocities of about -4.4 and -17.6 km s-1. A third, much weaker, component at about -21.7 km s-1 also appears to be present. Na I column densities for these components have been obtained by line-profile fitting, and estimates have been made of the N (Na I)/N (H) ratios. These are found to be consistent with standard diffuse interstellar clouds. Arguments are presented that these clouds are associated with the boundary between the local low-density interstellar bubble and the neighbouring Loop I bubble, at a distance between about 50 and 100 pc from the Sun. (author)