BC Cygni
star in the constellation Cygnus
BC Cygni (abbreviated to BC Cyg), also known as BD+37°3903, is a red supergiant or hypergiant pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.
It is considered a member of the Cygnus OB1 stellar association, and within it the open cluster Berkeley 87, which would place at a distance of 1,673 parsecs (5,000 ly) of the Solar System; it is less than a degree north of another variable red supergiant, BI Cygni. According to its Gaia Data Release 3 parallax, it is at about 1,700 pc.
BC Cygni was found to have a luminosity of 145,000 L☉ and an effective temperature of 2,858 K in the year 1900, and a luminosity of 112,000 L☉ and a temperature of 3,614 K in the year 2000. It is one of largest stars known, at its brightest and coolest calculated to be 1,553 R☉ compared to 856 R☉ at its hottest and faintest. If it were in the place of the Sun, its photosphere would engulf the entire inner Solar System and reach close to the orbit of Jupiter. With a mass of about 19 M☉, it is estimated that the stellar mass loss, as dust, as the atomic and molecular gas could not be evaluators is 3.2×10−9 M☉ per year.
Louisa Wells discovered that the star's brightness varied, based on the examination of 15 photographic plates. That discovery was announced in 1911. It was given its variable star designation, BC Cygni, in 1914.
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This entry incorporates text from “BC Cygni” 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.