Astronomers have imaged planetesimal belts in 74 planetary systems using the Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). These belts, composed of dust and rocks, were detected because of their unique size that allows for precise imaging. The study focuses on stars aged from young to middle-aged, similar to our Sun.
The REASONS survey has provided significant insights into exocometary belts, revealing where pebbles and comets are located within these structures. Due to the extremely cold temperatures (-250°C to -150°C), water is frozen as ice on these comets. Exocomets are massive rocks and ice boulders that collide in the belts, producing smaller pebbles observable with ALMA and SMA arrays.
The new images showcase a diverse range of belt structures, including narrow rings, wider disks, and multiple rings with eccentric orbits. These findings suggest the presence of undetectable planets or moons affecting the distribution of pebbles. The REASONS survey demonstrates the capabilities of the ALMA and SMA facilities in providing unprecedented insights into the universe.
The study’s author, Dr. Luca Matrà, noted that exocometary belts are found in at least 20% of planetary systems, including our own Solar System. The Kuiper Belt, a cometary belt in our Solar System, is thought to be the source of water for Earth through ancient comet impacts.
The REASONS dataset will enable future studies on the birth and evolution of exocometary belts, as well as follow-up observations with advanced telescopes like the James Webb Space Telescope.
Source: https://www.sci.news/astronomy/exocometary-belts-13660.html