{ "abstract": "RR Lyrae stars (RRLs) are valuable probes of both Milky Way assembly and stellar-evolution physics. Using a sample 6240 RRLs obtained in the first year of the Dark Energy Spectroscopic Instrument (DESI) survey, we investigate the metallicity of RRLs and its correlation with their pulsation properties. We find that (1) a clear correlation between period and [Fe/H] reinforces the view that the long-standing Oosterhoff dichotomy arises from the scarcity of intermediate-metallicity Galactic globular clusters hosting sizeable RRL samples; (2) high-amplitude short-period and small-amplitude short-period variables are comparatively metal-rich, with mean [Fe/H] = −1.39 ± 0.27 and −1.30 ± 0.28, respectively; (3) in double-mode pulsators (RRd), the metallicity declines smoothly with increasing fundamental-mode period, and anomalous RRd stars occupy a remarkably narrow [Fe/H] range relative to classical RRd stars; (4) this spectroscopic sample lets us, for the first time, place empirical constraints on the metallicity-dependent topology of the instability strip using phase-corrected effective temperatures and a large number of RRLs, where we observe an instability strip that moves towards cooler T eff with declining [Fe/H] with a width roughly consistent with stellar-evolution models; and (5) a subset of metal-rich RRLs exhibits orbits consistent with disk membership and halo kinematics. Our results confirm the tantalizing potential of DESI for Galactic and stellar astrophysics and highlight the importance of the even larger samples of RRLs and data-processing improvements forthcoming in future DESI data releases.", "abstract_shown": true, "affiliations": [ "University of Toronto", "Universidad de La Laguna (ULL)", "Instituto de Astrofísica de Canarias", "University of Arizona", "Observatório Nacional", "University of Edinburgh", "University of Cambridge", "University of California", "NSF NOIRLab", "University of California Observatories", "National Tsing Hua University", "Durham University", "Lawrence Berkeley National Laboratory", "Boston University", "Università degli Studi di Milano", "INAF-Osservatorio Astronomico di Brera", "University College London", "Universidad Nacional Autónoma de México", "Universidad de los Andes", "Institut d’Estudis Espacials de Catalunya (IEEC)", "University of Portsmouth", "Institute of Space Sciences", "Fermi National Accelerator Laboratory", "The University of Texas at Dallas", "Southern Methodist University", "Sorbonne Université", "Institució Catalana de Recerca i Estudis Avançats", "Institut de Física d’Altes Energies (IFAE)", "Instituto de Astrofísica de Andalucía (CSIC)", "Universitat Politècnica de Catalunya", "Sejong University", "CIEMAT", "University of Michigan" ], "article_type": null, "arxiv": "2505.10614", "author_total": 42, "authors": [ { "affs": [ 0 ], "name": "G. E. Medina", "orcid": "0000-0003-0105-9576" }, { "affs": [ 0 ], "name": "T. S. Li", "orcid": "0000-0002-9110-6163" }, { "affs": [ 1, 2 ], "name": "C. Allende Prieto", "orcid": "0000-0002-0084-572X" }, { "affs": [ 3, 4 ], "name": "L. Beraldo e Silva", "orcid": "0000-0002-0740-1507" }, { "affs": [ 5 ], "name": "A. Byström", "orcid": "0000-0002-5689-8791" }, { "affs": [ 0 ], "name": "R. G. Carlberg", "orcid": "0000-0002-7667-0081" }, { "affs": [ 5, 6 ], "name": "S. E. Koposov", "orcid": "0000-0003-2644-135X" }, { "affs": [ 7 ], "name": "M. Lambert", "orcid": "0000-0002-2527-8899" }, { "affs": [ 8 ], "name": "J. R. Najita", "orcid": "0000-0002-5758-150X" }, { "affs": [ 7, 9 ], "name": "C. Rockosi", "orcid": "0000-0002-6667-7028" }, { "affs": [ 10 ], "name": "N. Kizhuprakkat" }, { "affs": [ 11 ], "name": "A. H. Riley", "orcid": "0000-0001-5805-5766" }, { "affs": [ 12 ], "name": "J. Aguilar", "orcid": "0000-0003-0822-452X" }, { "affs": [ 13 ], "name": "S. Ahlen", "orcid": "0000-0001-6098-7247" }, { "affs": [ 14, 15 ], "name": "D. Bianchi", "orcid": "0000-0001-9712-0006" }, { "affs": [ 16 ], "name": "D. Brooks", "orcid": "0000-0002-8458-5047" }, { "affs": [ 12 ], "name": "T. Claybaugh" }, { "affs": [ 10 ], "name": "A. P. Cooper", "orcid": "0000-0001-8274-158X" }, { "affs": [ 17 ], "name": "A. de la Macorra", "orcid": "0000-0002-1769-1640" }, { "affs": [ 8 ], "name": "A. Dey", "orcid": "0000-0002-4928-4003" }, { "affs": [ 16 ], "name": "P. Doel", "orcid": "0000-0002-6397-4457" }, { "affs": [ 18 ], "name": "J. E. Forero-Romero", "orcid": "0000-0002-2890-3725" }, { "affs": [ 19, 20, 21 ], "name": "E. Gaztañaga" }, { "affs": [ 12 ], "name": "S. Gontcho A Gontcho", "orcid": "0000-0003-3142-233X" }, { "affs": [ 22 ], "name": "G. Gutierrez", "orcid": "0000-0003-0825-0517" }, { "affs": [ 23 ], "name": "M. Ishak", "orcid": "0000-0002-6024-466X" }, { "affs": [ 24 ], "name": "R. Kehoe", "orcid": "0000-0002-7101-697X" }, { "affs": [ 12 ], "name": "T. Kisner", "orcid": "0000-0003-3510-7134" }, { "affs": [ 12 ], "name": "M. Landriau", "orcid": "0000-0003-1838-8528" }, { "affs": [ 25 ], "name": "L. Le Guillou", "orcid": "0000-0001-7178-8868" }, { "affs": [ 8 ], "name": "A. Meisner", "orcid": "0000-0002-1125-7384" }, { "affs": [ 26, 27 ], "name": "R. Miquel", "orcid": "0000-0002-6610-4836" }, { "affs": [ 28 ], "name": "F. Prada", "orcid": "0000-0001-7145-8674" }, { "affs": [ 29 ], "name": "I. Pérez-Ràfols", "orcid": "0000-0001-6979-0125" }, { "affs": [ 30 ], "name": "G. Rossi" }, { "affs": [ 31 ], "name": "E. Sanchez", "orcid": "0000-0002-9646-8198" }, { "affs": [ 12 ], "name": "D. Schlegel", "orcid": "0000-0002-5042-5088" }, { "affs": [ 12 ], "name": "J. Silber", "orcid": "0000-0002-3461-0320" }, { "affs": [ 8 ], "name": "D. Sprayberry", "orcid": "0000-0001-7583-6441" }, { "affs": [ 32 ], "name": "G. Tarlé", "orcid": "0000-0003-1704-0781" }, { "affs": [ 8 ], "name": "B. A. Weaver" }, { "affs": [ 12 ], "name": "R. Zhou", "orcid": "0000-0001-5381-4372" } ], "bibtex": "https://research.draconitic.com/paper/5yk6amzfsd5y5.bib", "cited_by": 1, "doi": "10.3847/1538-4357/ae78cb", "fulltext_url": null, "id": "5yk6amzfsd5y5", "issns": [ "0004-637X", "1538-4357" ], "landing_url": "https://hal.science/hal-05780317v1", "language": "en", "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "hal", "0.phys" ], [ "hal", "1.phys.astr" ], [ "openalex", "3103|Stellar, planetary, and galactic studies" ] ], "openalex": "W4417092758", "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae78cb/pdf", "pmcid": null, "pmid": null, "published": "2026-10-01", "publisher": "American Astronomical Society", "ris": "https://research.draconitic.com/paper/5yk6amzfsd5y5.ris", "sources": [ { "first_seen": "2026-10-30T12:17:48Z", "native_id": "hal-05780317", "source": "hal", "url": "https://hal.science/hal-05780317v1" }, { "first_seen": "2026-10-30T12:18:11Z", "native_id": "10.3847/1538-4357/ae78cb", "source": "crossref", "url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae78cb" } ], "subjects": [ { "field": "astronomy", "origin": "openalex:3103|Stellar, planetary, and galactic studies", "subfield": "stellar" } ], "title": "The DESI Y1 RR Lyrae Catalog. II. The Metallicity Dependency of Pulsational Properties, the Shape of the RR Lyrae Instability Strip, and Metal Rich RR Lyrae", "title_text": "The DESI Y1 RR Lyrae Catalog. II. The Metallicity Dependency of Pulsational Properties, the Shape of the RR Lyrae Instability Strip, and Metal Rich RR Lyrae", "type": "peer-reviewed", "updated_at": "2026-10-30T12:18:11Z", "url": "https://research.draconitic.com/paper/5yk6amzfsd5y5", "venue": "The Astrophysical Journal", "versions": [] }