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 (SMEX AO). Eos observes molecular clouds in our galaxy and nearby planet forming disks to understand the link between star and planet formation and molecular hydrogen in galactic star forming regions. Eos does this using very long-slit, high resolution spectroscopy of far ultraviolet (FUV) emission from fluorescent molecular hydrogen (H₂), a powerful and underutilized FUV diagnostic. H₂ is the most abundant molecule in the universe, but is typically observed in the infrared (IR) or inferred via proxies such as CO. Eos will directly observe H₂ via fluorescence, which can be stimulated from a range of sources (shocks, interstellar UV radiation, bright stars, etc). Here we briefly describe the science objectives of Eos, as well as the instrument implementation.