Product Code Database
| temperature=3,535
| luminosity = 150,000
| metal=
| gravity=−0.5
| rotation=
| age_myr=>9
KY Cygni is a variable star red supergiant of spectral class M3Ia located in the constellation Cygnus. It is approximately 4,700 light-years away.
KY Cygni is heavily reddened due to interstellar extinction, losing an estimated 7.75 magnitudes at visual wavelengths. It would be a naked eye star if no light was lost.
Its properties are uncertain, but the temperature is around 3,500 K. A model fit based on K-band infrared brightness gives a luminosity of , corresponding to a radius of . Another model based on visual brightness gives an unexpectedly large luminosity of , with the difference due mainly to the assumptions about the level of extinction. The radius corresponding to the higher luminosity would be . These parameters are larger and more luminous than expected for any red supergiant, making them doubtful. More recently, integration of the spectral energy distributions across a full range of wavelengths from U band to the 60 micron microwave flux gives an even lower luminosity of , and a 2020 paper published a luminosity of , which give a smaller radius of using an effective temperature of 3,535K.
KY Cygni is a variable star with a large amplitude but no clear periodicity. At times, it varies rapidly, at others it is fairly constant for long periods. The photographic magnitude range is given as 13.5 - 15.5, while a visual range is 10.60 - 11.74.
Properties
KY Cygni is classified as a luminous red supergiant with a strong stellar wind. It is losing mass at around and has been described as a cool hypergiant.
See also
Notes
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