A team of European astronomers undertook a comprehensive study of 870 protoplanetary disks within the Orion A molecular cloud, a vast reservoir of gas and dust in the Orion constellation. By leveraging an unusually large dataset and applying innovative analytical methods, the researchers uncovered a clear pattern: the rate at which disk mass decreases is governed primarily by the system’s age. This trend holds across most environments, with exceptions arising near the hottest, most intense stars where external forces can accelerate mass loss. The implication is striking: within a radius of about 1,000 light-years from Earth, protoplanetary disks and their emerging planetary systems appear to follow a broadly similar evolutionary path. This work appears in a scholarly journal focused on astronomy and astrophysics. (Citation: Astronomy and Astrophysics)
The broader question guiding modern planetary science asks how other planetary systems might compare to the Solar System, what differences may exist, and how unique different systems are. A leading researcher, Zirk van Terwisga, from the German Astronomical Institute of the Max Planck Society in Heidelberg, explains the significance. He notes that prior to this study the dominant processes shaping disk evolution were not clearly understood. The new findings indicate that, when external disturbances are minimal, the amount of disk material available to form planets is tied to the system’s age rather than other environmental factors. (Citation: Astronomy and Astrophysics)
Orion A, a well-known region of young stars with protoplanetary disks, lies about 1,350 light-years from Earth and served as the focal point of the investigation. The research team relied on the Atacama Large Millimeter Array, perched on the Chainantor Plateau in Chile’s Atacama Desert, to quantify disk mass. ALMA operates as a linked network of 66 parabolic antennas that function together as a single telescope, with the ability to adjust angular resolution to suit the target. The scientists selected an observation mode that centered on a wavelength near 1.2 millimeters. At this frequency, the relatively cold disks emit strongly while the light from their central stars diminishes, making it easier to isolate the disk signal. This approach allowed the team to estimate the dust content by filtering out larger objects, such as rocks and nascent planets, providing a robust measure of the total mass contained in the planet-forming disks. (Citation: Astronomy and Astrophysics)