{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T18:28:41Z","timestamp":1791570521551,"version":"4.3.4"},"reference-count":57,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"21","funder":[{"DOI":"10.13039\/100013757","name":"Space Telescope Science Institute","doi-asserted-by":"publisher","award":["Program 4645"],"award-info":[{"award-number":["Program 4645"]}],"id":[{"id":"10.13039\/100013757","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.science.org"],"crossmark-restriction":true},"short-container-title":["Sci. Adv."],"published-print":{"date-parts":[[2026,5,22]]},"abstract":"<jats:p>Nereid, Neptune\u2019s third largest moon, is considered to be a captured irregular satellite because of its highly eccentric orbit. However, among irregular satellites, Nereid is an outlier: It is the largest, the closest to its host planet, and the most eccentric. We present James Webb Space Telescope near-infrared spectroscopy of Nereid that demonstrates that its composition is inconsistent with its suggested captured origin. We then simulate Nereid\u2019s early orbital history subsequent to Triton\u2019s capture to demonstrate a plausible dynamical pathway for a regular satellite formed in situ around Neptune to evolve to Nereid\u2019s present-day orbit. On the basis of the available spectroscopic and dynamical evidence, we propose that Nereid is not a body captured from the Kuiper belt but rather the sole surviving intact regular satellite of Neptune.<\/jats:p>","DOI":"10.1126\/sciadv.aeb1429","type":"journal-article","created":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T18:00:40Z","timestamp":1779300040000},"update-policy":"https:\/\/doi.org\/10.34133\/aaas_crossmark","source":"Crossref","is-referenced-by-count":2,"title":["Nereid as a regular satellite of Neptune"],"prefix":"10.1126","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4778-6170","authenticated-orcid":true,"given":"Matthew","family":"Belyakov","sequence":"first","affiliation":[{"name":"Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7451-4704","authenticated-orcid":true,"given":"M. Ryleigh","family":"Davis","sequence":"additional","affiliation":[{"name":"Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9665-8429","authenticated-orcid":true,"given":"Ian","family":"Wong","sequence":"additional","affiliation":[{"name":"Space Telescope Science Institute, Baltimore, MD 21218, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7094-7908","authenticated-orcid":true,"given":"Konstantin","family":"Batygin","sequence":"additional","affiliation":[{"name":"Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8255-0545","authenticated-orcid":true,"given":"Michael E.","family":"Brown","sequence":"additional","affiliation":[{"name":"Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.245.4917.500"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0032-0633(01)00131-3"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature04792"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.icarus.2011.05.003"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/311355a0"},{"key":"e_1_3_2_7_2","doi-asserted-by":"crossref","unstructured":"O. 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