RT Aurigae
star in the constellation Auriga
RT Aurigae (RT Aur, 48 Aurigae) is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth. Although its brightness is variable, it is consistently visible to the naked eye under good observing conditions.
RT Aurigae is an F to G type Classical Cepheid variable which varies from magnitude +5.00 to +5.82 with a period of 3.728309 days. The variability was discovered in 1905, by an English schoolmaster and amateur astronomer, Thomas Hinsley Astbury. It was quickly recognised as a member of the class of Cepheid variables, but their nature was not understood at that time. Radial velocity changes were detected corresponding to the brightness variations, but the idea that these were caused by stellar pulsations and temperature changes was largely dismissed in favour of orbital motions of a binary star. More accurate observations eventually proved beyond doubt that the brightness variations were caused by pulsations in the atmospheres of the stars, with the stars being smallest and hottest near maximum brightness.
RT Aurigae has been suspected to be a spectroscopic binary system, but this has not been confirmed. The strongest evidence was found in 2013 using CHARA array optical interferometry. The companion would be 6.7 magnitudes fainter than the supergiant primary, cooler and fainter than an F0 main sequence star.
“RT Aurigae” enters the record as star in the constellation Auriga. Crown Archives preserves that source wording while asking what Aurigae, star and constellation can confirm, complicate or overturn.
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This entry incorporates text from “RT Aurigae” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.