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Arxiv: Investing in the Unrivaled Potential of Wide-Separation Sub-Jupiter Exoplanet Detection and Characterisation with JWST -- Strategic Exoplanet Initiatives with HST and JWST White Paper Published: 8/14/2024 4:18:26 PM Updated: 8/14/2024 4:18:26 PM

Paper abstract: We advocate for a large scale imaging survey of nearby young moving groupsand star-forming regions to directly detect exoplanets over an unexplored rangeof masses, ages and orbits. Discovered objects will be identified early enoughin JWST's lifetime to leverage its unparalleled capabilities for long-termatmospheric characterisation, and will uniquely complement the known populationof exoplanets and brown dwarfs. Furthermore, this survey will constrain theoccurrence of the novel wide sub-Jovian exoplanet population, informingmultiple theories of planetary formation and evolution. Observations withNIRCam F200W+F444W dual-band coronagraphy will readily provide sub-Jupiter masssensitivities beyond ~0.4" (F444W) and can also be used to rule out somecontaminating background sources (F200W). At this large scale, targets can besequenced by spectral type to enable robust self-referencing for PSFsubtraction. This eliminates the need for dedicated reference observationsrequired by GO programs and dramatically increases the overall scienceobserving efficiency. With an exposure of ~30 minutes per target, thesub-Jupiter regime can be explored across 250 targets for ~400 hours ofexposure time including overheads. An additional, pre-allocated, ~100 hours ofobserving time would enable rapid multi-epoch vetting of the lowest massdetections (which are undetectable in F200W). The total time required for asurvey such as this is not fixed, and could be scaled in conjunction with theminimum number of detected exoplanet companions.