0 Assigned ID: 820 ----- Attempting Submission 1 (Fri Mar 06 21:51:29 GMT 2020) ----- HST Phase I Proposal 820 successfully submitted. Receipt: # 820-1 ----- Attempting Submission 2 (Fri Mar 06 23:57:21 GMT 2020) ----- HST Phase I Proposal 820 successfully submitted. Receipt: # 820-2 ----- Attempting Submission 3 (Sat Mar 07 00:23:12 GMT 2020) ----- Spectroscopic analyses are a crucial tool for investigating properties of stars and supernovae (SNe) which in turn provide constraints on stellar and galactic evolution. CMFGEN is a time-dependent non-LTE radiative transfer code designed to model the spectra of stars and SNe. It is available online and is used at many research universities and institutions around the world. We plan to extend and enhance the capabilities of CMFGEN. These improvements will be particularly useful for analyzing existing spectra of massive stars in the HST archive, and for analyzing spectra of OB and Wolf-Rayet (WR) stars and Luminous Blue Variables (LBVs) that will be obtained as part of the Director's Discretionary Legacy program, ULLYSES. Despite extensive developments over the last few years there are still many unanswered questions related to stellar evolution, and in particular to massive star evolution. While we understand the basic principles behind radiation-driven winds, there are issues regarding the accuracy of derived mass-loss rates. Mass-loss rates are a key ingredient in stellar evolution calculations. Despite the ubiquity of binaries among massive stars, the role of binarity in producing WR stars is still debated. Mixing, which brings CNO-processed material to the stellar surface, is not fully understood. More recently it has been realized that the iron convection zone can inflate the radius of the star. Does this inflation explain the discrepancy between derived and evolutionary radii of WN and WC stars, and what role does it play in other stars? Spectroscopic analyses provide a crucial means of addressing these and other important topics. Hillier is the developer of CMFGEN which is available online at www.pitt.edu/~hillier. It is a non-LTE, time-dependent, radiative transfer code designed to model the spectra of massive stars and supernovae. He has also developed radiative transfer codes, and Monte Carlo codes, to model axisymmetric stellar winds and/or SN ejecta. Hillier has coauthored over 150 refereed publications. Stellar Physics and Stellar Types 0 Regular false false true false false SUPPORTED