The Structure of the Local Interstellar Medium. II. Observations of D I, C II, N I, O I, Al II, and Si II toward Stars within 100 parsecs

Abstract

Moderate and high-resolution measurements (R ~ 40,000) of interstellar resonance lines of D I, C II, N I, O I, Al II, and Si II (light ions) are presented for all available observed targets located within 100 pc which also have high-resolution observations of interstellar Fe II or Mg II (heavy ions) lines. All spectra were obtained with the Goddard High Resolution Spectrograph or the Space Telescope Imaging Spectrograph instruments aboard the Hubble Space Telescope. Currently, there are 41 sightlines to targets within 100 pc with observations that include a heavy ion at high resolution and at least one light ion at moderate or high resolution. We present new measurements of light ions along 33 of these sightlines, and collect from the literature results for the remaining sightlines that have already been analyzed. We greatly increase the number of sightlines with useful LISM absorption line measurements of light ions by using knowledge of the kinematic structure along a line of sight obtained from high resolution observations of intrinsically narrow absorption lines, such as Fe II and Mg II. Because high resolution observations of heavy ions are critical for understanding the kinematic structure of local absorbers along the line of sight, we include 18 new measurements of Fe II and Mg II in an appendix. We present a statistical analysis of the LISM absorption measurements, which provides an overview of some physical characteristics of warm clouds in the LISM, including temperature and turbulent velocity. This complete collection and reduction of all available LISM absorption measurements provides an important database for studying the structure of nearby warm clouds, including ionization, abundances, and depletions.