Separating Flare and Secondary Atmospheric Signals with <tt>RADYN</tt> Modeling of Near-infrared JWST Transmission Spectroscopy Observations of TRAPPIST-1

Abstract Although TRAPPIST-1’s temperate planets have the highest transmission signals of any known system, flares contaminate 50%–70% of transits at the 1000 ppm level, far above 100 ppm secondary atmospheric signals. Efforts to mitigate flare contamination and assess impacts on radiation environments are each hampered by a lack of empirical spectral analysis and physics-based modeling. We present spectrotemporal analysis and radiative-hydrodynamic modeling of 5.5 hr of NIRISS and NIRSpec observations of six TRAPPIST-1 flares of 2.2–8.7 × 10 30 erg. The flare lines and continua are characterized using grid searches of RADYN beam-heating models spanning 10 4 times in electron beam parameters. Best-fit models indicate these flares result from moderate-intensity beams with emergent electron fluxes of F e = 10 12 erg s −1 cm −2 and energies ≤37 keV, although all models overpredict the Paschen jump. These models predict X-ray and extreme UV (XUV), far-UV, and near-UV counterparts to the IR peak fluxes of 8.9–28.9 × 10 27 , 4.3–13.9 × 10 26 , and 3.4–11.4 × 10 27 erg s −1 , respectively. Scaling the flare rate into the XUV suggests flaring contributes 1.35 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow/> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.15</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.0</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mo>×</mml:mo> </mml:math> quiescence yr −1 . We bin integrations of similar flare effective temperature to construct fiducial flare spectra from 2000 to 4500 K, in order to develop separate empirical and RADYN -based mitigation pipelines. Both pipelines are applied to all 5.5 hr of R = 10 data, resulting in maximum residuals from 1 to 2.8 μ m of 100–140 ppm and typical residuals of 54 ± 14 and 65 ± 17 ppm for the empirical and RADYN -based pipelines, respectively. Injection testing supports a 3 σ detection capability for CO 2 atmospheres with features of 150–250 ppm, with weak evidence (Bayes factor ≈ 3) still obtained at 130 ppm. Our results motivate multiwavelength observations to improve model fidelity and test high-energy predictions.