BC Cygni
BC Cygni is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.
It is considered a member of the stellar Cygnus OB1 association, and within it the open cluster Berkeley 87.2 which would place at a distance of 1,500 parsecs of the Solar System; however, according to the measure of the parallax by the satellite Hipparcos. It is less than a degree north of another variable red supergiant, BI Cygni.
BC Cygni was calculated to have an effective temperature of 2,858 to 3,614 K and to vary between. The size at its brightest and coolest has been calculated to be compared to at the hottest and faintest. It is one of largest stars known. If it were in the place of the Sun, its photosphere would engulf the orbit of Jupiter assuming the maximum radius of. With a mass of about, it is estimated that the stellar mass loss, as dust, as the atomic and molecular gas could not be evaluators is per year. This mass is an indication that this star will end up exploding as a supernova.
The brightness of BC Cyg varies from visual magnitude +9.0 and +10.8 with a period of 720 ± 40 days. Between 1,900 and 2,000 appears to have increased its average brightness of 0.5 magnitudes.
