Eos: a FUV spectroscopic mission to observe molecular hydrogen in molecular clouds

Eos is a mission concept to be proposed to the expected 2025 NASA Small Explorers Announcement of Opportunity. Eos observes molecular clouds in our galaxy to understand the link between star and planet formation and molecular hydrogen in galactic star forming regions. Eos does this using very long-slit, moderate resolution spectroscopy of UV emission from fluorescent molecular hydrogen, a powerful and underutilized FUV diagnostic. H2 is the most abundant molecule in the universe, but is typically observed in the IR or observed via proxies such as CO. Eos will directly observe H2 via fluorescence, which can be stimulated from a range of sources (shocks, external energy fields, bright stars, etc). Here we briefly describe the science objectives of Eos, as well as the instrument implementation.