The dust reservoirs observed in two type IIP supernovae, SN 2004et and SN 2017eaw, both in the medium-sized, face-on spiral galaxy NGC 6946 about 22 million light-years away, is radiatively heated to 100-150 K (minus 173 to minus 123 degrees Celsius, minus 280 to minus 190 degrees Fahrenheit) by ongoing shock interaction with the circumstellar medium. Hubble image of NGC 6946, the host galaxy of both SNe 2004et and 2017eaw. Bottom left-hand panel:...
