Sure enough, the debris disks surrounding other stars seem to disappear rather quickly as soon as the star is about 400 million years old, according to Habing and Carsten Dominik, also of Leiden Observatory. In work appearing in this week's issue of Nature, Habing and Dominik and a group of French and Spanish colleagues used ISO to observe a sample of 84 bright stars at the relatively long infrared wavelengths thought to indicate cold dust far from the star. The similarity to our own solar system is striking. All this adds up to a convincing scenario for how solar systems are born and evolve, but the details are poorly understood and many questions remain. For instance, it's unclear how much the environment of a star can disturb or inhibit the formation of planets.
Many stars are part of binaries or multiple systems.
But if the distance between the stars is comparable to the size of our solar system, the gravitational interplay between them seems to disrupt any disk, according to astronomer Eric Jensen of Swarthmore College in Swarthmore, Pennsylvania. Planet formation also seems to be thwarted in large, star-forming regions such as the Orion Nebula, where the energetic ultraviolet radiation of massive young stars evaporates neighboring dust disks before planet formation can commence. Thus a large gathering of young stars may not be the best place for planets to form. The strange bright clumps observed at millimeter wavelengths in the debris disks of the stars Vega, Beta Pictoris, and Epsilon Eridani pose another mystery. Despite such remaining mysteries, one thing seems clear.