Presentation #127.02 in the session New Mission Concepts.
Planetary atmospheres are significantly governed by the host star’s ultraviolet (UV) emission through photochemistry and photoevaporation and are best probed by UV spectroscopy where higher atomic and molecular opacities yield bigger signals. UV-SCOPE (Ultraviolet Spectroscopic Characterization Of Planets and their Environments) will be a dedicated facility designed to accomplish the broad population-wide studies needed to understand the underlying physical drivers of exoplanet atmospheres and answer today’s most pertinent questions in exoplanet science:
— How much mass is being lost to space across the diverse planet population? What is sculpting the radii of the small-planet population? — What are the driving chemical processes in the upper atmospheres of highly irradiated Jovian-like exoplanets (hot Jupiters)? How and when do they form clouds and hazes? — What influence does the high energy stellar environment have on atmospheric evolution, chemistry, and habitability?
Each of UV-SCOPE’s three driving science cases stems directly from these questions and probes the evolution and chemistry of a different, albeit linked, layer of a planet’s atmosphere. We will determine atmospheric mass loss from sub-Neptunes and super-Earths, the chemistry in the upper atmosphere of hot Jupiters, and the multi-timescale evolution of stellar high-energy radiation driving photochemistry in the lower atmospheres of terrestrial planets.
UV-SCOPE will observe the UV transmission spectra of transiting exoplanets orbiting young and old stars ranging in spectral type, plus the spectra of stars with which to map the variability, flaring, and evolution of exoplanet high-energy environments. UV-SCOPE will achieve simultaneous wavelength coverage from the far-UV (FUV) to the near-UV (NUV); 1205–4000 Å, including the strong and diagnostic Ly-α emission line. This observing strategy will be executed from L2 where, compared to low-Earth-orbit, the UV backgrounds are negligible and uninterrupted long observations, crucial for transmission spectroscopy and stellar activity monitoring, are possible.