0 Assigned ID: 1290 ----- Attempting Submission 1 (Thu Feb 28 21:14:05 GMT 2013) ----- Relatively little is known about the chemical evolution of the element phosphorus, despite its relatively large abundance in the Sun and its importance for biological life. The goal of this archive proposal is to establish the chemical evolution trend of phosphorus, extending our knowledge from solar metallicity to stars with less than 1/1000th the solar metallicity. Previous studies have used weak near-infrared P I lines to establish phosphorus abundance trends from -1.0 < [Fe/H] < 0. We have identified a strong P I doublet in the UV at 2136 Angstroms, which is present in the spectra of 22 stars available in the HST archives. Our study will (1) improve on the limited observations of the abundance trend at high metallicity and extend it to metallicities lower by ~2 dex and (2) determine whether [P/Fe] flattens out towards lower metallicities (like the alpha-elements Mg, Si, Ca, and Ti) or whether it continues to increase (like Co and Zn). Our results will provide the first tight constraints on the nucleosynthesis of phosphorus and its production sites in the early Universe. We request one semester of funding to support a graduate student to lead the spectral analysis work, one month of summer salary, and miscellaneous travel and publication costs. COOL STARS Default Small false true false false false SUPPORTED