Oral Presentation
ALMA detects CI in the beta Pictoris debris disk
Presenter: Gianni Cataldi (Subaru telescope, NAOJ)
Debris disks can be seen as the extrasolar analogues of the asteroid belt or the Kuiper belt. Since they are an outcome of the planet formation process, observations of debris disks are useful to constrain theories of planet formation.
Debris disks are characterised by a considerable amount of dust, produced via collisional grinding of planetesimals or comets. However, a small but growing fraction of debris disks also show a gaseous component. A prime example is the archetypal debris disk around the young (~23 Myr) A-star beta Pictoris, where the gas has been extensively studied. Importantly, the gas is of secondary origin rather than leftover from the protoplanetary phase. For example, colliding dust grains or evaporating comets can produce gas. Thus, studying the gas allows us to constrain the composition of the building blocks of planets.
I will present the first detection of the CI 492 GHz emission line in a debris disk, from ALMA band 8 observations of beta Pic. The data show an asymmetry similar to what is seen in recent ALMA observation of CO. This is surprising and strongly challenges our view of the gas production and evolution in this disk. I will discuss the implications of the new data regarding the scenarios that have been put forward to explain the CO asymmetry, i.e. a giant collision or a resonance induced by a migrating planet.
asiaa.sinica.edu.tw