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

¹ INAF – Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy
² Max Planck Institute for Astronomy, Konigstuhl 17, 69117 Heidelberg, Germany
³ Centre for Astronomy, Department of Physics, National University of Ireland Galway, University Road, Galway H91 TK33, Ireland
⁴ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
⁵ Astronomy Unit, School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK
⁶ Department of Astronomy, Columbia University, 538 W. 120th Street, Pupin Hall, New York, NY, USA
⁷ Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, The Netherlands

^★★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 11 December 2025
Accepted: 1 March 2026

Abstract

The evolution of planet-forming disks and the processes of planet formation influence each other, and both of them are possibly impacted by the local environment. Extensive high-resolution imagery of disks across space and time is the best tool for determining their evolution. We compiled a comprehensive list of disk-bearing young stars with near-IR high-contrast images available. The sample sums up to 268 sources, including 51 targets with no prior publications, which makes this study the largest of its kind and the most extensive release of IR disk images to date. Our census reveals very diverse disk and ambient morphologies. Disks in Lupus are bright, in Chamaeleon they are faint, in Corona Australis and Taurus they are frequently surrounded by ambient emission. Disks experience an abrupt increase in IR brightness between 2 Myr and 5 Myr. The earliest IR disk cavities around single stars arise after 2–3 Myr, which explains why young disks are faint in the near-IR and determines which disks can live longer. Well-known, high-longevity disks (>8 Myr) are always bright. Ambient material is detected in more than 20% of young sources but the fraction drops with time. We find clear correspondence for the presence of ambient material with the stellar variability, near-IR excess, and mass accretion rate as well as, in turn, with spirals and shadows in disks. Half of the disks with ambient material show spirals while none of them show rings. We therefore propose that the spirals and the disk warps responsible for shadows are generally induced by late infall from the medium, and that this also affects stellar accretion. The emerging picture proves the fundamental role of the environment for disk evolution and planet formation.