Do planetary systems also experience a turbulent childhood phase? Images captured by the ALMA telescope network provide a glimpse of this 'tumultuous childhood', where young planets undergo violent shocks and redefine their orbits.
The Atacama Large Millimeter/submillimeter Array (ALMA), located in Chile, conducted an observation campaign targeting 24 dust disks surrounding young stars. These structures, much less bright than protoplanetary disks, correspond to the period following the emergence of young planets, when objects resulting from this process collide repeatedly.
Protoplanetary disks observed by ALMA as part of the ARKS project.
Credit: Sebastian Marino, Sorcha Mac Manamon, ARKS collaboration
These debris disks represent the remnants left after the birth of planets, a phase where impacts between celestial bodies continue to shape the systems. They are more difficult to detect than gas-rich disks due to their faint glow, but ALMA was able to capture their radio emissions to reveal their structure.
The collected data display a range of shapes, including multiple rings, extended halos, and pronounced asymmetries. This morphological diversity reveals a very active period, marked by orbital reorganizations and large shocks, similar to the one that gave rise to our Moon.
Moreover, our own Solar System preserves witnesses from that era, such as the Kuiper Belt located beyond Neptune's orbit. This icy region, populated by comets and asteroids resulting from ancient collisions, constitutes a local echo of the same phenomena observed by ALMA around other stars.
Meredith Hughes from Wesleyan University stated that these images fill a gap in our understanding, linking the early formation stages to systems that have reached maturity. The study, published in
Astronomy & Astrophysics, thus helps to reconstruct the dynamic history of planets.
This research opens new avenues for analyzing how planetary systems transform after their early youth. By scrutinizing these disks, astronomers can better understand the mechanisms that shape worlds, including our own, over time.
How ALMA works
ALMA implements a technique called interferometry, which merges the signals captured by its 66 antennas spread across the Atacama Desert. This configuration allows for very high angular resolution, much greater than that of a single telescope, by simulating a very large instrument.
By recording the radio emissions emitted by dust and molecules in space, ALMA can map fine details at very great distances. This capability is fundamental for studying faint objects such as debris disks, invisible to classical optical telescopes.
ALMA's sensitivity to millimeter and submillimeter wavelengths provides information on the composition and dynamics of disks. This helps researchers grasp how matter distributes and interacts during the advanced phases of planetary formation.
This feat has revolutionized astronomical observation, making processes once inaccessible visible. ALMA therefore remains a leading instrument for exploring the evolution of stellar and planetary systems.