As a solar system evolves, the disk from which the planets will form is initially bright and thick with dust. During the first 10 million years or so, gaps appear in the disk as planets form and clear out paths. Over time, the debris disk thins from gravitational interactions with planets. Steady pressure from the starlight and stellar winds push out the dust as well. Eventually, only a thin debris disk remains at the edge of the system.
Video Credits: NASA / JPL-Caltech / R. Hurt (SSC/Caltech)
This picture was taken using SPHERE (the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument), a planet-hunting instrument mounted on ESO’s Very Large Telescope (VLT) in Chile. It shows a series of disrupted, concentric rings in the inner region of the debris disc surrounding a young star named HD 141569A about 370 light-years away. The image shows what is known as a transition disc, the brief stage between the protoplanetary phase, when planets have not yet formed, and a later time when planets have coalesced, leaving the disc populated only by dusty debris.
The area shown in this image has a diameter of just 200 times the Earth-to-Sun distance. Several features are visible because of the excellent detail from the SPHRE data, including a bright, prominent ring with well-defined edges which is so asymmetric that it appears as a half-ring. We can also see multiple clumps, several concentric ringlets, and a pattern that looks like a spiral arm. These structures are asymmetric, something for which astronomers do not currently have a firm explanation. It is possible that this phenomenon is caused by the presence of planets, but so far planets large enough to do this haven’t been found in the system.