{"paper":{"title":"Spinning out of focus: The challenge of rotational line broadening in exoplanet reflection spectroscopy","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Rotational broadening hides reflected exoplanet signals unless properly modeled in misaligned systems.","cross_cats":[],"primary_cat":"astro-ph.EP","authors_text":"A. Kaminski, A. Quirrenbach, A. Reiners, A. Schweitzer, D. Cont, D. Montes, E. Nagel, E. Palle, F. Yan, G. Bergond, G. Morello, I. Ribas, J. A. Caballero, K. Molaverdikhani, L. Nortmann, P. J. Amado, S. Czesla, Th. Henning, T. O. Winterhalder, V. J. S. B\\'ejar","submitted_at":"2026-05-15T18:00:01Z","abstract_excerpt":"Detecting light reflected off the dayside of an exoplanet in high-resolution spectroscopic data has proved to be a notoriously difficult endeavour. Despite several attempts, the faint signal has yet to be detected. We present a new effort at finding reflection signatures and show how a strong rotational broadening of the reflected spectrum can complicate this objective. We introduce a new figure of merit that quantifies the favourability of different systems for a reflection study, the reflection spectroscopy metric. Applying this metric, we identify the KELT-9 system, which features a highly "},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The injection-recovery test reveals the critical importance of taking rotational broadening into account when dealing with systems featuring rapidly rotating stars and large spin-orbit misalignments.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the modeled rotational broadening kernel and the injected signal template accurately represent the true reflected spectrum shape and noise properties in the CARMENES KELT-9 time series.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Introduces a reflection spectroscopy metric and uses KELT-9 injection-recovery tests to demonstrate that rotational line broadening from rapid stellar rotation and large misalignments must be included when assessing detectability of exoplanet reflected spectra.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Rotational broadening hides reflected exoplanet signals unless properly modeled in misaligned systems.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"2993774922bd4f5c39774ecdd968d54cb8db3f778c6bf35a8cfc73300e10c991"},"source":{"id":"2605.16491","kind":"arxiv","version":1},"verdict":{"id":"5f282557-1a61-481b-9069-9c463a56410f","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-19T21:58:58.955292Z","strongest_claim":"The injection-recovery test reveals the critical importance of taking rotational broadening into account when dealing with systems featuring rapidly rotating stars and large spin-orbit misalignments.","one_line_summary":"Introduces a reflection spectroscopy metric and uses KELT-9 injection-recovery tests to demonstrate that rotational line broadening from rapid stellar rotation and large misalignments must be included when assessing detectability of exoplanet reflected spectra.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the modeled rotational broadening kernel and the injected signal template accurately represent the true reflected spectrum shape and noise properties in the CARMENES KELT-9 time series.","pith_extraction_headline":"Rotational broadening hides reflected exoplanet signals unless properly modeled in misaligned systems."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.16491/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"doi_title_agreement","ran_at":"2026-05-19T22:31:19.625418Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T22:12:41.304926Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"ai_meta_artifact","ran_at":"2026-05-19T19:33:23.104805Z","status":"skipped","version":"1.0.0","findings_count":0},{"name":"claim_evidence","ran_at":"2026-05-19T19:21:57.022985Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"e3fdca00c1c7de1c6390eafe84313627dbcd3c11b6067aefeb4b7d12145a3c36"},"references":{"count":129,"sample":[{"doi":"10.1051/0004-6361/201014343","year":null,"title":"Clouds in the atmospheres of extrasolar planets. 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Thermal emission spectra of Earth-like planets influenced by low and high-level clouds","work_id":"160aed58-52e6-4079-9c06-6498f3ca96a9","ref_index":1,"cited_arxiv_id":"1105.3568","is_internal_anchor":true},{"doi":"10.1086/309160","year":null,"title":"Albedo and Reflection Spectra of Extrasolar Giant Planets","work_id":"a9c99fe8-3dd1-4759-8ceb-836b5a5651b6","ref_index":2,"cited_arxiv_id":"astro-ph/9910504","is_internal_anchor":true},{"doi":"10.1088/2041-8205/789/1/l20","year":2041,"title":"The Albedos of Kepler's Close-in super-Earths","work_id":"73e7fb18-bc34-4229-af30-125d4dfb4be2","ref_index":3,"cited_arxiv_id":"1405.3798","is_internal_anchor":true},{"doi":"10.3847/1538-3881/ac6b97","year":null,"title":"Reflected Spectroscopy of Small Exoplanets II: Characterization of Terrestrial Exoplanets. , keywords =. doi:10.3847/1538-3881/ac6b97 , archivePrefix =. 2204.13816 , primaryClass =","work_id":"f4b69819-e862-4dec-b558-836a09973380","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/1538-3881/ab79a5","year":2003,"title":"2020, AJ, 159, 175, doi: 10.3847/1538-3881/ab79a5","work_id":"e4e8ba7e-f65a-4520-8d21-36541f0b0e12","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":129,"snapshot_sha256":"76b95e3dc27c4bb9f14591931a518c8ba64f8bd1bc651408ea2a5c53f8887ef3","internal_anchors":34},"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"}