ISO view of Cassiopeia A

A ring of bright blobs depicts newly created cosmic dust, in the vicinity of a massive star that exploded in about AD 1680. This image of supernova remnant Cassiopeia A was obtained by ESA's Infrared Space Observatory (ISO). It gives astronomers new insight into the processes in which newly-formed chemical elements, released by stellar explosion, create dust as they cool. These products enrich the clouds of gas and dust between the stars and help to make possible the formation of planets and perhaps living things, in the vicinity of stars as yet unborn. Cassiopeia A lies about 11,000 light-years away, in the direction of the familiar W of the northern constellation Cassiopeia. It is the remnant of the most recent supernova explosion in the Milky Way Galaxy. The ISO image gives the first detailed picture of Cassiopeia A at infrared wavelengths of 11-12 micron, which are clearly observable only from a satellite above the Earth's atmosphere. The dusty shell is a hollow sphere, about 5.5 light-years in diameter. The ring-like appearance is due to the greater density of dust seen tangentially from the Earth's vicinity. Also visible towards the top left corner of the ISO image is a streak of dust formed by a high-speed of material flung out in the stellar explosion. [Image Date: 01-07-97] [97.08.001-004]