Planet-forming disks and their environment across regions and time from the full NIR census

Vol. 709
6. Interstellar and circumstellar matter

Planet-forming disks and their environment across regions and time from the full NIR census

Extreme adaptive optics observations in the near infrared (NIR) over the past 15 years have provided high angular resolution images of planet-forming disks that reveal their diverse structure and offer unique clues as to their evolution history. Using this rich dataset, Antonio Garufi and collaborators have compiled the most complete list so far of disk-bearing young stars with NIR high-contrast images, consisting of 268 sources and including 51 targets with no prior publication. Thanks to the large size of their sample, these authors have been able to study subsamples from individual star-forming regions (mainly Taurus, Ophiuchus, Chamaeleon, Lupus, Upper Sco, and Orion), as well as from systems with a different geometry and age. Their analysis reveals very diverse disk and ambient morphologies. Disks in Lupus are bright, in Chamaeleon they are faint, and in Corona Australis and Taurus they are frequently surrounded by ambient emission. In general, disks experience an abrupt increase in IR brightness between 2 and 5 Myr. The emerging picture from this study is one of disk diversity and evolution driven by the connection between the disk and a stochastically evolving local interstellar medium via late infall and interaction with other stars.