This site contains links to images and animations related to a study by Scott Kenyon and me on the possibility that the Sun had a close encounter with another star around 4 billion years ago. This work shows that a distant object in our solar system, known as Sedna, could have been placed on its observed orbit by such an encounter. We also found that the Sun and the passing star could have exchanged planetary material, as illustrated below. For more information, please check out Scott's web page on Sedna. Or check out these animations:
Still images from a simulation|
Click on each image for a high-resolution version:
A passing star and the Sun may have exchanged small planets and dust as they flew by each other. These images illustrate this process: Initially, the dust and planets orbit in circular disks around their parent star. As the Sun and the passing star approach each other (upper left image), the force of gravity can yank small bodies from one star to the other (middle images). Once the stellar encounter is complete, the disks contain a mixture of captured and indigenous planets (lower right).