Young star. Computer artwork showing jets (orange) emanating from the poles of a young star. A dark circumstellar disc of dust is seen edge-on at 90 degrees to the jets. Discs such as this are thought to be the precursors of planetary systems, with planets forming as the dust coalesces. The jets (bipolar molecular outflows) are thought to form as material ejected from the star is forced into two jets by the rotation of the disc.