"Teenage years of planetary systems": Debris disks around stars imaged
Dust disks around stars where exoplanets form have been imaged for years. However, they become darker and elude research – until now.
(Image: Sebastián Marino, Sorcha Mac Manamon, and the ARKS collaboration)
For the first time, astronomers have succeeded in imaging faint debris disks around other stars that remain after the formation of planets. The images show sharply defined edges, multiple rings, extended halos, and unexpected arcs and clumps, all of which point to the influence of young exoplanets, explains the Max Planck Institute for Astronomy. The images were captured using the ALMA (Atacama Large Millimeter/Submillimeter Array) radio telescope network in Chile. Using direct imaging and radial velocity measurements, the research group is simultaneously searching for exoplanets in these systems. Even without them, the images are of great value; the group refers to them as a hitherto “missing page in the family album of planets.”
Chaotic phase around young stars
The 24 depicted debris disks are the cosmic equivalent of the teenage years of planetary systems, explains the research institution. They are particularly difficult to image because they are significantly fainter than the bright, gas-rich disks in which planets form. The images now published are not images in the classical sense, but processed radio signals originating from dust particles and molecules within these disks. The structures represent that phase in the early development of a planetary system that is still characterized by massive collisions. In our case, the Moon formed during this period, and the planets were vying for their final positions. They could even have swapped these positions during that phase.
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The images show a real diversity, explains project leader Sebastián Marino from the University of Exeter. A more detailed analysis of the images is now intended to reveal, for example, “whether chaotic features are inherited, formed by planets, or originated from other cosmic forces.” If an answer to this can be found, it could reveal whether the history of our solar system was unique or normal. In total, the team has imaged 24 such debris disks; the project is called ARKS, or “ALMA survey to Resolve exoKuiper belt Substructures.” This suggests that the Kuiper Belt at the edge of the solar system corresponds to this phase of development. The work is presented in a scientific article in the journal Astronomy & Astrophysics.
(mho)
