MY Cephei

light curve for MY Cephei, plotted from ASAS-SN data Observations of the open cluster NGC 7419 in 1954 showed that four of its members were luminous red stars, most likely red supergiants. In addition, an unusually red star was found to be variable and probably an even more luminous supergiant. This star was given the variable star designation MY Cephei in 1973 in the 59th name-list of variable stars. MY Cephei is classified as semiregular variable star of sub-type SRc, indicating it is a cool supergiant, although its pulsational period is not known. It has been observed as bright as magnitude 14.4 and as faint as magnitude 15.5. ==Distance==

The distance of MY Cephei is assumed to be around or based on it being a member of the NGC 7419 open cluster. Gaia Early Data Release 3 gives a parallax of for MY Cep, ==Stellar properties==

The spectral type of MY Cephei is given in the General Catalogue of Variable Stars as M6–7 Iab, indicating the star is an intermediate-size luminous supergiant star, MY Cephei is a very luminous, cool and large extreme supergiant star, with a luminosity more than 100,000 times that of the Sun () and a radius in excess of a thousand times the Sun's radius (). It is likely the most luminous, coolest, and the largest supergiant star in its open cluster, The mass of MY Cephei is uncertain, but expected to be around 14.5 times the Sun's mass (). Older studies frequently calculated even more lower temperatures and an estimated radius of . ==See also==