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Planet formation is far from understood. Observations of Free Floating Planets (FFPs), on the one hand, and of planets in tight stellar binaries, on the other, are challenging our leading (Core Accretion) scenario for planet formation strongly. This classical framework requires a prolonged epoch of gentle accumulation of small solids into ever larger bodies, yet both FFPs and planets in binaries surely experienced extremely violent dynamics with ejection and collision velocities approaching a few to tens of km/sec. We have recently showed that disc fragmentation due to Gravitation Instability, the competing scenario for planet formation, presents a natural explanation for the surprisingly abundant FFP population. In this talk I will present analytical arguments and numerical simulations that detail this emergent paradigm. I will try and connect formation of FFPs, planets in binaries, and stellar binaries themselves, into one coherent picture.

BIO

Sergei Nayakshin obtained his MPhys degree from the Moscow Engineering Physics Institute in 1993, and his PhD from the University of Arizona, Tucson, in 1998. He then held research Fellowships at the NASA Goddard Space Flight Centre, Maryland (1998-2001), and the Max Planck Institute for Astrophysics, Garching (2001-2005). He was appointed a lecturer in the University of Leicester, UK, in 2005, and later became a full Professor, the post that he currently holds. His research extended to topics in the physics of accretion discs in Active Galactic Nuclei, the extreme star formation around Sgr A* in the Galactic Centre, feedback from AGN in general, and Sgr A* in particular. In the last dozen years his main focus has been planet formation via protoplanetary disc fragmentation, and episodic accretion (FU Ori outbursts) of young protostars.

Host: Chris Ormel