{"paper":{"title":"The CARMENES search for exoplanets around M dwarfs. Period search in H$\\alpha$, Na I D, and Ca II IRT lines","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"A. Kaminski, A. Quirrenbach, A. Reiners, B. Fuhrmeister, D. Galad\\'i-Enr\\'iquez, D. Montes, E. D\\'iez Alonso, E. N. Johnson, E. W. Guenther, F. Bauer, I. Ribas, J. A. Caballero, J. H. M. M. Schmitt, M. Cort\\'es-Contreras, M. K\\\"urster, M. Lafarga, M. Zechmeister, P. J. Amado, P. Sch\\\"ofer, S. Czesla, S. Dreizler, S. V. Jeffers, V. J. S. B\\'echar","submitted_at":"2019-01-16T08:23:17Z","abstract_excerpt":"We use spectra from CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, to search for periods in chromospheric indices in 16 M0 to M2 dwarfs. We measure spectral indices in the H$\\alpha$, the Ca II infrared triplet (IRT), and the Na I D lines to study which of these indices are best-suited to find rotation periods in these stars. Moreover, we test a number of different period-search algorithms, namely the string length method, the phase dispersion minimisation, the generalized Lomb-Scargle periodogram, and the Gauss"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1901.05173","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":""},"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"}