fix typos in the abstract 2011320272 Assigned ID: 2400 ----- Attempting Submission 1 (Fri Apr 09 22:55:41 GMT 2021) ----- HST Phase I Proposal 2400 successfully submitted. Receipt: # 2400-1 ----- Attempting Submission 2 (Fri Apr 09 23:07:38 GMT 2021) ----- We propose to create a set of stellar evolution and atmosphere models designed specifically for the study of multiple stellar populations in globular clusters. No such comprehensive set exists today and yet the study of multiple populations is one of the great triumphs of the Hubble Space Telescope, as well as being an active field of research. We will compute state-of-the-art stellar models for a range of metallicities that cover the observed range of globular clusters, -2.5 < [Fe/H] < 0, with an alpha-enhanced chemical composition but also, crucially, including the light-element abundance variations that are peculiar to globular cluster stellar populations. The light-element variations will include a range of helium enhancements motivated by observational constraints as well as the enrichment of nitrogen and sodium and the depletion of carbon and oxygen. The abundance pattern will be used self-consistently in stellar evolution models and stellar atmosphere models, including synthetic spectra. The evolutionary models will include stellar masses from 0.1 to 5 solar masses, suitable for studying both the ancient globular clusters and the young globular clusters, e.g., in the Magellanic Clouds. The models will be made available in all HST photometric camera/filter systems and will be made freely available to the community in an easy-to-use format through a website that we maintain. These stellar models will be a valuable resource for the astronomical community for years to come and will enhance the value of HST's legacy in the realm of multiple stellar populations in globular clusters. Charlie Conroy has expertise in stellar populations research ranging from resolved stellar populations in the Milky Way to the interpretation of unresolved stellar populations in distant galaxies. Prof. Conroy is an expert in the use of the ATLAS model atmosphere and SYNTHE spectral synthesis codes that feature prominently in this proposal. Aaron Dotter is an expert in stellar evolution modeling and the interpretation of globular cluster color-magnitude diagrams. Dr. Dotter is well versed in the computation of stellar evolution models including the Dartmouth models and the MIST models and is a lead developer of the MESA stellar evolution code. Anna F. Marino is an expert in globular cluster spectroscopy and the study of multiple stellar populations in globular clusters. Antonino P. Milone is an expert in globular cluster photometry and a pioneer in the study of multiple stellar populations in globular clusters. These investigators collaborated to produce the 2015 study on NGC 6752 that plays a prominent role in this proposal. Stellar Populations and the Interstellar Medium Stellar Physics and Stellar Types 0 Regular false false false true false SUPPORTED