HD images of the cosmic labor from which planets are born

The cosmic labor that leads to the birth of new planets has been captured in unprecedented detail by the exoAlma project , peering into the dusty protoplanetary disks of 15 young stars using the Atacama Large Millimeter/submillimeter Array ( Alma ) radio interferometer in Chile. The images, which open a new era in planet-hunting, are presented in 17 papers published in a special issue of the Astrophysical Journal of Letters. The authors of the studies include several Italian researchers, such as Andrea Isella of Rice University in Texas, professors at the University of Milan Stefano Facchini, Giuseppe Lodato and Giovanni Rosotti, and two PhD students from the same university, Pietro Curone and Cristiano Longarini.

“The new approaches we have developed to collect these data and images are like switching from reading glasses to high-powered binoculars: they reveal a whole new level of detail in these planet-forming systems,” says Richard Teague, exoAlma project scientist.

The team targeted dusty protoplanetary disks around 15 young stars to map the motions of the gas in detail to uncover the processes that form planetary systems and, in some cases, identify telltale signs of baby planets (such as gaps and rings in dusty disks around stars, swirling motions in the gas caused by a planet's gravity, and physical changes in the disk that could signal the presence of a planet).

Unlike traditional planet-hunting methods, which look for the direct light of a young planet, exoALMA looks for the effects that planets have on their surroundings, potentially allowing it to detect much younger worlds. "It's like trying to spot a fish by looking at the ripples in a pond, rather than trying to see the fish itself," says Christophe Pinte, an astrophysicist at the Institut d'Astrofísica et Planetologie de Grenoble and co-leader of the exoALMA team.

The data collected by the project have allowed the density , temperature and velocity structure of planet-forming disks to be mapped in unprecedented detail. "These disks are much more dynamic than we imagined ," comments Isella. "We are seeing evidence of gravitational interactions, instabilities and the initial influence of planets before they are fully formed."

“exoAlma - adds Facchini of the University of Statale - provides observations at a level never achieved before of the physical mechanisms at play during the early stages of the formation of planets similar to those of the Solar System, revealing dynamic interactions between the birth environments of these new worlds and the planets themselves in formation”.