Assigned ID: 595 ----- Attempting Submission 1 (Fri Mar 07 21:24:52 GMT 2008) ----- This purpose of this program is to better understand the ISM and its extinction effects by greatly increasing the high-quality sample of carbon abundance measurements from the neutral ISM. Carbon is an abundant element that exists in several phases in the interstellar medium: dust, gaseous atoms/ions and gaseous molecules. The phase distribution of this element is a fundamental characteristic of interstellar clouds that governs their physics. Yet the abundance of carbon has been measured in only 13 neutral interstellar sight lines, 7 of which have known extinction characteristics. The HST archive contains a wealth of data on interstellar carbon that has not yet been tapped. We propose to use archival STIS measurements of the interstellar C II 1334 A absorption to significantly increase the sample of interstellar carbon abundance measurements. Nineteen of our proposed 23 sight lines have extinction curves determined for them; this will nearly quadruple the number of sight lines with both measured C abundances and derived extinction curves. The enhanced sample of measurements will allow us to gain insight into both the gas and dust-phases of the interstellar medium, perhaps solve the problem of the carbon crisis, and illuminate the role of carbon-based grains as extinction carriers.

ISM AND CIRCUMSTELLAR MATTER 12 60263 false 0.0 0.0 false false false false false SUPPORTED