Born in spirals: forming planets in young protoplanetary discs - Cristiano Longarini
When: Friday, November 6, 2026, 3:00 PM - 4:00 PM
Where: G. O. Jones, Room 610, Mile End
Speaker: Cristiano Longarini (Institute of Astronomy, University of Cambridge)
/filters:format(webp)/prod01/channel_322/school-of-physical-and-chemical-sciences/media/school-of-physical-and-chemical-sciences/images/seminar-images/Longarini_seminar.jpeg)
Title: Born in spirals: forming planets in young protoplanetary discs
Abstract:
High-resolution ALMA observations suggest that planet formation is already well underway in the earliest phases of disc evolution, when discs are still massive, self-gravitating and strongly coupled to their environment. How planetary cores can form so early remains an open question, as standard core accretion scenarios struggle to operate on such short timescales. In this talk, I will discuss the physical processes active during the earliest phase of disc evolution, such as gravitational instability. I will then present a hybrid planet formation pathway, in which the spiral arms of a gravitationally unstable disc trap solid particles and drive the dust itself to gravitational collapse, forming cores of 1–10 Earth masses at tens of au within 10^4–10^5 yr. I will discuss the conditions under which this mechanism can operate, and then follow these cores through gas accretion and migration to compare the resulting planet population with the observed demographics of exoplanets.