Dr. Giovanni Rosotti

University of Cambridge

Studying planet formation in the era of ALMA

Abstract:

The field of proto-planetary discs is progressing enormously thanks to ALMA. The general spirit of my talk will be to show how theory plays a fundamental role for interpreting these observations. On one side, the high angular resolution of ALMA enables to study discs in exquisite detail. I will discuss how the patterns of bright rings and dark gaps now routinely observed in discs can be explained by the youngest exoplanets ever found. I will show that the minimum planet mass observable is in the super-Earth/giant planetary core regime, thus enabling a large population of forming planets to be uncovered. While most observations have focused up to now on the continuum emission, I will discuss the prospects for detecting planet-disc interaction in gas emission lines. However, observing a gap does not prove that there is a planet. I will show for example how the innermost gap in the disc around Tw Hya is best explained by photo-evaporation rather than by a planet.
On the other side, thanks to the extreme sensitivity of ALMA entire surveys of the disc population are now becoming possible, giving us a chance to test our models of disc evolution. I will discuss in particular how these surveys can shed light on which mechanism is responsible for driving accretion onto young stars, discriminating between the two competing theories of angular momentum transport by viscosity and angular momentum removal by winds. Finally, I will discuss how studying disc evolution in binaries could also help to test our models of disc evolution.

Location: 31 Fitzwilliam Place, D02 XF86

Upcoming seminars:
https://www.dias.ie/2017/10/02/astronomy-and-astrophysics-seminar-schedule-2017/