{"id":2746,"date":"2026-10-30T19:34:20","date_gmt":"2026-10-30T10:34:20","guid":{"rendered":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/?p=2746"},"modified":"2026-10-30T19:34:20","modified_gmt":"2026-10-30T10:34:20","slug":"2026-10-28","status":"publish","type":"post","link":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/2026\/10\/30\/2026-10-28\/","title":{"rendered":"2026-10-28"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-bright-blue-color\">Physics meets data at survey scale: what stellar spectra can (and cannot) tell us<\/mark><\/h2>\n\n\n\n<p class=\"has-text-align-right\">Speaker: Mingjie Jian (Cambridge University)<\/p>\n\n\n\n<p>Abstract:<\/p>\n\n\n\n<p>Spectroscopic surveys are about to deliver millions of stellar spectra, and turning them into reliable stellar parameters and chemical abundances is increasingly a modelling problem rather than a data problem. Data-driven methods are fast, but they are only as good as the models and labels they learn from; physics-based spectral synthesis is transparent, but it is expensive and inherits the assumptions of its model atmospheres, atomic data and line formation. In this talk I will discuss how the two approaches can meet. Using high-resolution optical and near-infrared spectra of open clusters, I will show how forward modelling helps decide which spectral features genuinely trace abundances and which reflect other stellar physics, and what such measurements reveal about the chemical evolution of the Galactic disc, taking elements such as phosphorus as examples. I will then present recent developments in PySME aimed at survey-scale analysis, together with a physics-informed neural network that emulates stellar model atmospheres while respecting their physical constraints, as a step towards differentiable, end-to-end modelling of stellar spectra. I will close with prospects for upcoming surveys.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Physics meets data at survey scale: what stellar spectra can (and cannot) tell us Speaker: Mingjie Jian (Cambr &hellip; <a href=\"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/2026\/10\/30\/2026-10-28\/\" class=\"more-link\"><span class=\"screen-reader-text\">&#8220;2026-10-28&#8221; \u306e<\/span>\u7d9a\u304d\u3092\u8aad\u3080<\/a><\/p>\n","protected":false},"author":31,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2746","post","type-post","status-publish","format-standard","hentry","category-1"],"_links":{"self":[{"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/posts\/2746","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/users\/31"}],"replies":[{"embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/comments?post=2746"}],"version-history":[{"count":1,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/posts\/2746\/revisions"}],"predecessor-version":[{"id":2747,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/posts\/2746\/revisions\/2747"}],"wp:attachment":[{"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/media?parent=2746"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/categories?post=2746"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/seminars\/colloquium\/wp-json\/wp\/v2\/tags?post=2746"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}