{"paper":{"title":"Mitigating Charge Migration in JWST NIRISS Reveals That KELT-7 b is a Metal-enriched Ultra-hot Jupiter Orbiting a Young Metal-rich Star","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.IM"],"primary_cat":"astro-ph.EP","authors_text":"Arika Egan, Carlos Gasc\\'on, Daniel P. Thorngren, David K. Sing, Duncan A. Christie, Erin M. May, Guangwei Fu, Harry Baskett, Joshua D. Lothringer, Katherine A. Bennett, Kevin C. Schlaufman, Lakeisha M. Ramos Rosado, Le-Chris Wang, Mei Ting Mak, Mercedes L\\'opez-Morales, Myles Pope, Natalie H. Allen, Nathan J. Mayne, Patrick McCreery, Sagnick Mukherjee, Stephen P. Schmidt, Zafar Rustamkulov","submitted_at":"2026-07-07T18:24:45Z","abstract_excerpt":"We present the first panchromatic JWST transmission spectrum of an ultra-hot Jupiter, combining NIRISS and NIRSpec observations to constrain KELT-7\\,b's atmospheric properties. We show evidence for charge migration in our NIRISS SOSS observation between 1--1.5~$\\mu$m, a wavelength range crucial to test for enhanced H$^-$ previously inferred from HST WFC3/IR G141 observations. We mitigate charge migration by fitting the ramp after extracting 1D stellar spectra at the group level. This ``late-ramp-fit'' method accurately calculates KELT-7\\,b's transmission spectrum between 1--1.5~$\\mu$m at highe"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.06708","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.06708/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}