{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.w-virginis-variable","code":"thing-q936076","url":"https://ver.cy/models/thing/q936076/","name":"W Virginis variable","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.SPC"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A class of Type II Cepheid variable stars with pulsation periods of about 10 to 20 days, named after the prototype W Virginis, which are old, low-mass, metal-poor stars found in globular clusters and the galactic halo and are fainter than classical Cepheids of the same period.","purpose":"Let an agent explain W Virginis variables by properties, distinction from classical Cepheids, use as distance indicators and observation data.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Type II Cepheid","Old, metal-poor stars","Fainter than classical Cepheids","Distance indicators"],"structure":{"bundles":[{"id":"properties","name":"Properties","description":"What they are.","layers":[{"id":"star","name":"Star","description":"Stellar properties.","findings":[{"id":"star-finding","name":"Star","description":"Stellar properties.","questions":[{"text":"What are the period, luminosity and metallicity of this star?","kind":"measurement"},{"text":"Which population does it belong to?","kind":"provenance"}]}]},{"id":"classify","name":"Classify","description":"Type II subclasses.","findings":[{"id":"classify-finding","name":"Classify","description":"Subclass.","questions":[{"text":"Is the star a W Virginis, BL Herculis or RV Tauri variable?","kind":"definition"},{"text":"Which criteria decide?","kind":"definition"}]}]}]},{"id":"distinction","name":"Distinction","description":"Cepheid types.","layers":[{"id":"classical","name":"Classical","description":"Versus classical Cepheids.","findings":[{"id":"classical-finding","name":"Classical","description":"Classical versus Type II.","questions":[{"text":"How do W Virginis stars differ from classical Cepheids?","kind":"definition"},{"text":"How was the distinction discovered, according to historians of astronomy?","kind":"provenance"}]}]},{"id":"history","name":"History","description":"Distance scale history.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How did confusing the two types affect early distance estimates?","kind":"provenance"},{"text":"Who resolved it?","kind":"provenance"}]}]}]},{"id":"distances","name":"Distances","description":"Standard candles.","layers":[{"id":"relation","name":"Relation","description":"Period-luminosity.","findings":[{"id":"relation-finding","name":"Relation","description":"Period-luminosity relation.","questions":[{"text":"What period-luminosity relation applies to Type II Cepheids?","kind":"provenance"},{"text":"How is it calibrated?","kind":"provenance"}]}]},{"id":"use","name":"Use","description":"Applications.","findings":[{"id":"use-finding","name":"Use","description":"Applications.","questions":[{"text":"How are W Virginis stars used to measure distances to globular clusters?","kind":"definition"},{"text":"What uncertainties apply?","kind":"boundary"}]}]}]},{"id":"observing","name":"Observing","description":"Data.","layers":[{"id":"data","name":"Data","description":"Light curves.","findings":[{"id":"data-finding","name":"Data","description":"Light curves.","questions":[{"text":"Where can light curves and catalogue entries be found?","kind":"provenance"},{"text":"Which surveys observe them?","kind":"provenance"}]}]},{"id":"amateur","name":"Amateur","description":"Observing.","findings":[{"id":"amateur-finding","name":"Amateur","description":"Amateur observing.","questions":[{"text":"Can this star be observed by amateurs?","kind":"boundary"},{"text":"How can observations be reported?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Report W Virginis stars and their properties from published catalogues.","Explain their use in distance measurement and how they differ from classical Cepheids."],"mustNot":["Present a star's classification as certain when the catalogue lists it as uncertain.","Misattribute observations or discoveries."],"requiresHuman":["Changing a star's classification in a public catalogue."]},"ethics":{"considerations":["Correct attribution credits observers, including amateurs.","Confusing Cepheid types once distorted the cosmic distance scale; accuracy matters."],"affectedParties":["Astronomers, including amateur observers","Students"]},"owners":{"steward":"Nobody: a class of stars; astronomical catalogues record them.","roles":[],"masterSystems":["Variable star catalogues"]},"relations":[{"target":"Q1393939","type":"parent","note":"registry parent class"},{"target":"Type II Cepheid","type":"related","note":"category"},{"target":"W Virginis","type":"related","note":"prototype"},{"target":"classical Cepheid","type":"related","note":"related class"},{"target":"R Coronae Borealis variable","type":"related","note":"other variable class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.w-virginis-variable","Wikidata: Q936076 (https://www.wikidata.org/wiki/Q936076)","GCVS type: CWA variable star type"]},"properties":{"applicability":"required","items":["pulsation period: about 10-20 days - typical"]},"recognition":{"applicability":"required","items":["Periods of about 10-20 days","Found in globular clusters and the halo","Classical Cepheids are younger and more luminous","Pulsating yellow supergiant-like stars with regular light curves, seen mainly in old stellar populations."]},"capabilities":{"applicability":"required","items":["describe W Virginis star properties","distinguish them from classical Cepheids","explain their period-luminosity relation","find light curves and catalogues"]},"hazards":{"applicability":"required","items":["Confusing with classical Cepheids in distance work","Misclassifying peculiar stars"]},"interfaces":{"applicability":"required","items":["General Catalogue of Variable Stars classification"]},"context":{"applicability":"required","items":["Stellar astrophysics and distance measurement.","W Virginis stars","BL Herculis stars (shorter periods)","RV Tauri stars (longer periods)","peculiar W Virginis stars"]}},"sources":[{"title":"Wikidata item Q936076: W Virginis variable","url":"https://www.wikidata.org/wiki/Q936076","note":"identity and sense of the item"},{"title":"Wikipedia: W Virginis variable","url":"https://en.wikipedia.org/wiki/W_Virginis_variable","note":"general description of the item"}],"openQuestions":["Should each subclass be a separate entry?","How should catalogues be linked?","How should distance calibrations be recorded?"],"resources":{"spec":"/models/things/publications/thing-q936076/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q936076/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-11T15:19:38Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:52:03+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}