Extremely massive Kuiper Belts around 49 Ceti and HD 21997?

Explaining the observations of carbon monoxide around the A-type stars 49 Ceti and HD 21997 with a ~400 Earth mass comet belt.

Zuckerman and Song: A 40 Myr Old Gaseous Circumstellar Disk at 49 Ceti: Massive CO-Rich Comet Clouds at Young A-Type Stars

Hmmmm.

And now a press release.

More on the 49 Ceti disc - details on some of the star-grazing comets, preliminary estimates of a super-solar C/O ratio.

Miles, Roberge & Welsh "UV Spectroscopy of Star-Grazing Comets within the 49 Ceti Debris Disk"
http://arxiv.org/abs/1511.01923