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Jessica Donaldson


My research focuses on debris disks, which are dusty disks around other stars. The dust in these disks are thought to be formed by destructuve collisions between larger planetesimals. Essentially, debris disks are analogs to the Solar System's Kuiper Belt, a ring of icy and rocky bodies that may have brought volatiles like water to the terrestrial planets.

I study relatively young (~30 Myr old) debris disks using the Herschel Space Observatory. Herschel is an infrared observatory that can image the cold dust surrounding the star. By combining this data with observations at other wavelengths, we can model the properties of the disk.


The plot on the left is a spectral energy distribution, or SED, which shows how the brightness of the star and the disk change as a function of wavelength. At shorter wavelengths, the light from the star overwelms the disk. At longer wavelengths, the star is dimmer, but the emission from the cold dust is at its brightest. The red line is a best fit model to the disk that shows the disk to be a ring of large dust grains with a hole of with a radius ~ 50 AU that contains very little or no dust. This inner hole may indicate the presence of one or more planets.

This work is part of the Herschel Open Time Key Programme Gas in Protoplanetary Systems.