We present recent near-infrared detections of circumstellar disks around the two old PMS Herbig stars HD 141569 and HD 100546 obtained with the HST/NICMOS2 camera. They reveal extended structures larger than 350-400 AU in radius. While the HD 100546 disk appears as a continuous disk down to 40 AU, the HD 141569 environment seems more complex, splitted at least into two dust populations. As a convincing example, the full modeling of the disk surrounding HR 4796, another old PMS star, is detailed and confronted with more recent observations.
@article{arxiv.astro-ph/0010217,
title = {Dust disks around old Pre Main-Sequence stars: HST/NICMOS2 scattered light images and modeling},
author = {J. C. Augereau and A. M. Lagrange and D. Mouillet and F. Menard},
journal= {arXiv preprint arXiv:astro-ph/0010217},
year = {2007}
}