A dead star within a shroud of nebula, Helix image ISOCAM
As if stars wished to keep their privacy during these critical stages of their lives, their births and deaths usually occur within thick and opaque clouds of dust (nebulae). But infrared beams manage to escape these dusty regions, enabling ISO to see them.
The origin of planets
ISO searched for discs or rings of matter around stars. These are considered to be the first stage of planet formation, hence they are called 'protoplanetary discs'.