Addressing the mystery of exozodiacal dust

Séminaire IPAG de Amy Bonsor & Steve Ertel (IPAG), jeudi 17 janvier 2013 à 11h00, IPAG seminar room

Exozodiacal dust is hot dust at a distance of few AU down to the sublimation radius around main sequence stars. Although expected to be present in analogy to our own zodiacal dust, first observations of this phenomenon revealed surprising results and major differences to our own Solar System. Following time scale arguments, the dust cannot be produced at this position in a steady state collisional cascade of larger bodies as in a normal debris disk. On the other hand, transient events are unlikely because of their low probability and the large fraction of stars showing this phenomenon. Thus, there has been no scenario proposed, yet, that is able to explain the the phenomenon in its entirety.

In this talk, we will present an overview of the exozodi phenomenon. In the first half, Steve will introduce the observational background, present our own survey using near-infrared interferometric observations (VLTI/PIONIER, CHARA/FLUOR), and give future perspectives. In the second half, Amy will review in detail the theoretical scenarios suggested to explain the phenomenon, and present the own theoretical work done by our team using N-body and comet evaporation models.