Astronomy - Ch. 8: Origin of the Solar System (14 of 19) Early Migration of the Jovian Planets

In this video I will explain Mars is so small and why asteroid belt did not form a planet.

Next video in this series can be seen at:

[fredpalmer]

Are you talking about the "Grand Tack Hypothesis?
"Unlike the classical scenario, the orbital excitation and mass depletion of the asteroid belt in the Grand Tack model are both essentially created during the inward-then-outward migration of Jupiter and Saturn (Walsh et al. 2011; Jacobson & Walsh 2015). In this model, the giant planets crossed the asteroid belt twice. First, during their inward migration stage, the gas giants compress the distribution of planetary embryos and planetesimals inside Jupiter's orbit into a narrow disc around 1 au. A fraction of these objects is also scattered outwards. Secondly, during the outward migration phase, the giant planets scatter inwards a fraction of planetesimals beyond 2–3 au enough to repopulate the asteroid belt region, with a dynamically excited population of small bodies carrying altogether a small total mass.

An alternative to the Grand Tack scenario to produce the confined disc and a mass deficient asteroid belt could be invoked so that a lot of solid material drifted to within 1 au by gas drag, leaving the region beyond 1 au substantially depleted in mass. This idea is very appealing in a broad context of planet formation. This is because it is often invoked to produce a large pile-up of mass in the inner disc to explain the formation of close-in super-Earths (e.g. Boley & Ford 2013; Chatterjee & Tan 2014). Moreover, it could also be consistent with modern ideas on planetesimal formation and planetary growth based on the drift and accretion of pebbles (Lambrechts & Johansen 2014; Lambrechts, Johansen & Morbidelli 2014; Johansen et al. 2015). Particles drifting towards the star can produce in principle discs of solids of any radial gradient in the resulting mass distribution. Therefore, the goal of this paper is to test whether any of these gradients could explain at the same time the small mass of Mars and the properties of the asteroid belt (mass deficit and inclination excitation). In other words, can we match these constraints without invoking a dramatic event within the inner Solar system (such as a Grand Tack)?

An alternate to the Grand Tack Hypothesis is Terrestrial planet formation constrained by Mars and the structure of the asteroid belt
André Izidoro, Sean N. Raymond, Alessandro Morbidelli, Othon C. Winter
Published: 09 September 2015

[memofromessex]

Thanks for the video. I was struggling a little bit with the concept of Grand Tack Theory!

[Wya]

I thought Jupiter did migrate inwards by losing angular momentum (transferring it to other objects passing by), but then was brought back into place by Saturn, as soon it gained enough mass to enter in resonance with Jupiter?