HR4796 debris disk Qphi and Uphi images

Even though we only model the radial profiles along (or close to) the semi-major axis of the disk, our best-fit model is not only in good agreement with our observations but also with previously published datasets (from near-IR to sub-mm wavelengths). We find that the reference radius is located at 76.4+/-0.4au, and the disk has an eccentricity of 0.076_-0.010_^+0.016^, with the pericenter located on the front side of the disk (north of the star).

We find that small dust grains must be preferentially released near the pericenter to explain the observed brightness asymmetry. Even though parent bodies spend more time near the apocenter, the brightness asymmetry implies that collisions happen more frequently near the pericenter of the disk. Our model can successfully reproduce the shape of the outer edge of the disk, without having to invoke an outer planet shepherding the debris disk.

With a simple treatment of the effect of the radiation pressure, we conclude that the parent planetesimals are located in a narrow ring of about 3.6au in width.