{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.by-draconis-variable","code":"thing-q797219","url":"https://ver.cy/models/thing/q797219/","name":"BY Draconis 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 rotating variable stars, mostly cool main-sequence stars of spectral types K and M, whose brightness varies by a few tenths of a magnitude as starspots rotate in and out of view, often with flares; the prototype is BY Draconis, and many are young or in close binaries.","purpose":"Let an agent explain BY Draconis variables by mechanism, properties, relation to flare stars and observation data.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Rotational modulation by starspots","Cool main-sequence stars","Often flare activity","Small amplitude"],"structure":{"bundles":[{"id":"mechanism","name":"Mechanism","description":"Why they vary.","layers":[{"id":"spots","name":"Spots","description":"Starspots.","findings":[{"id":"spots-finding","name":"Spots","description":"Starspots.","questions":[{"text":"How do starspots and rotation produce the light variations?","kind":"definition"},{"text":"What is the rotation period?","kind":"measurement"}]}]},{"id":"activity","name":"Activity","description":"Magnetic activity.","findings":[{"id":"activity-finding","name":"Activity","description":"Magnetic activity.","questions":[{"text":"How is the variability linked to magnetic activity and flares?","kind":"definition"},{"text":"Do activity cycles occur, according to studies?","kind":"provenance"}]}]}]},{"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 spectral type, age and binarity of this star?","kind":"provenance"},{"text":"How large is the amplitude?","kind":"measurement"}]}]},{"id":"classify","name":"Classify","description":"Classification.","findings":[{"id":"classify-finding","name":"Classify","description":"Classification.","questions":[{"text":"Is the star classed as BY Draconis, a flare star or both?","kind":"provenance"},{"text":"Which criteria apply?","kind":"definition"}]}]}]},{"id":"science","name":"Science","description":"Wider relevance.","layers":[{"id":"exoplanets","name":"Exoplanets","description":"Host star activity.","findings":[{"id":"exoplanets-finding","name":"Exoplanets","description":"Host star activity.","questions":[{"text":"How does starspot activity affect exoplanet detection and habitability studies?","kind":"provenance"},{"text":"Which methods correct for it?","kind":"definition"}]}]},{"id":"sun","name":"Sun","description":"Solar analogy.","findings":[{"id":"sun-finding","name":"Sun","description":"Solar analogy.","questions":[{"text":"How do these stars compare with sunspot activity on the Sun?","kind":"definition"},{"text":"What do they reveal about young stars?","kind":"provenance"}]}]}]},{"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 for this star be found?","kind":"provenance"},{"text":"Which surveys observe it?","kind":"provenance"}]}]},{"id":"amateur","name":"Amateur","description":"Observing.","findings":[{"id":"amateur-finding","name":"Amateur","description":"Amateur observing.","questions":[{"text":"Can amateurs detect the small variations with photometry?","kind":"boundary"},{"text":"How can observations be reported?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Report BY Draconis stars and their properties from published catalogues.","Explain starspot variability in general terms."],"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.","Overstated claims about habitability of planets around flaring stars mislead the public."],"affectedParties":["Astronomers, including amateur observers","Students"]},"owners":{"steward":"Nobody: a class of stars; astronomical catalogues record them.","roles":[],"masterSystems":["Variable star catalogues"]},"relations":[{"target":"Q2168098","type":"parent","note":"registry parent class"},{"target":"rotating variable star","type":"related","note":"category"},{"target":"BY Draconis","type":"related","note":"prototype"},{"target":"flare star","type":"related","note":"related class"},{"target":"W Virginis variable","type":"related","note":"other variable class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.by-draconis-variable","Wikidata: Q797219 (https://www.wikidata.org/wiki/Q797219)","GCVS type: BY variable star type"]},"properties":{"applicability":"required","items":["Rotation period:  days - Rotation period is inferred from recurring starspot modulation while accounting for spot evolution and possible period ambiguities.","Photometric variability amplitude:  mag - Variability amplitude is measured from a light curve in a specified passband over a stated observing interval.","Effective temperature:  K - Effective temperature is inferred from calibrated spectra or photometry using stellar atmosphere models."]},"recognition":{"applicability":"required","items":["Rotation-linked variability","K and M dwarfs","Eclipsing binaries show sharp periodic dips instead","Cool red or orange dwarf stars with small quasi-periodic brightness variations."]},"capabilities":{"applicability":"required","items":["describe the starspot mechanism","identify BY Draconis characteristics","relate them to flare stars and activity cycles","find light curves and catalogues"]},"hazards":{"applicability":"required","items":["Confusing rotational and pulsational variability","Misattributing flares"]},"interfaces":{"applicability":"required","items":["General Catalogue of Variable Stars classification"]},"context":{"applicability":"required","items":["Stellar activity research and variable star observing.","single BY Draconis stars","BY Draconis stars in binaries","young active dwarfs","stars also classed as flare stars"]}},"sources":[{"title":"Wikidata item Q797219: BY Draconis variable","url":"https://www.wikidata.org/wiki/Q797219","note":"identity and sense of the item"},{"title":"Wikipedia: BY Draconis variable","url":"https://en.wikipedia.org/wiki/BY_Draconis_variable","note":"general description of the item"}],"openQuestions":["Should flare stars be linked or merged?","How should survey data be linked?","How should activity cycles be recorded?"],"resources":{"spec":"/models/things/publications/thing-q797219/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q797219/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 2026-10-07T10:10:32+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}