Has anyone in these forums witnessed a simulation of solar system accretion? I'll assume no, and will share visuals for whoever is interested if I manage to visit one.
Back to a question asked, as to what type of solar simulation, I'm actually asking about typical times to run a type that scientists use to model its history of formation, but my earlier link says:
We examine 141 N-body simulations of terrestrial planet late-stage accretion that use the Grand Tack scenario, coupling the collisional results with a hafnium-tungsten (Hf-W) isotopic evolution model.
They don't bother saying how quick their simulation is to start up.
But the next part seems to say that the simulated assumptions in the model are unlikely to match reality. My skills for interpretating their jargon is limited so it's faster to simply assume yes, that's what it's saying (from a barely educated guess):
Accretion in the Grand Tack scenario results in faster planet formation than classical accretion models because of higher planetesimal surface density induced by a migrating Jupiter. Planetary embryos which grow rapidly experience radiogenic ingrowth of mantle tungsten which is inconsistent with the measured terrestrial value, unless much of the tungsten is removed by an impactor core that mixes thoroughly with the target mantle.
This
next source goes farthest by hinting at the time the simulation takes to run. I'll quote that part and also the parts I'm interested in seeing from a simulation:
stage of planet formation is typically modeled using N-body accretion simulations, which begin with a swarm of embryos and planetesimals in orbit around a star, then calculate how their gravitational interactions and collisions lead to the formation of larger planets.
Definitely good if the simulation is able to reproduce, in principle, something like what we observe today, even if obviously it'll differ.
(Also please keep in mind the gist of my original question, which is a general 'what's the expected startup and run time for typical simulations, the type that can reveal how our solar system formed'? All the rest here is simply an elaborated reply to requested info)
So for the quote below, an ability to reproduce results similar to what we observe is ideal, as long as we can also tweak and customize for 'what if' scenarios to answer hypothetical questions, to test ideas, etc:
Ideally, we could constrain the early dynamical history of the Solar System (e.g., orbital properties of the giant planets) by determining which initial configuration is best able to reproduce all of the properties of the planets. The key properties that were targeted to be reproduced in previous studies included the number, masses, semimajor axes, eccentricities, inclinations, formation timescales, and water contents of the terrestrial planets, as well as the angular momentum deficit (AMD) and radial mass concentration (RMC) of the bulk planetary system, and the mass stranded in the asteroid belt (Raymond et al., 2009).
In any simulation that can potentially reproduce our solar system (from a similar stellar cloud?), obviously the possibility of Earth sized (or even Earth like) planets is desirable:
Each of these early studies was able to produce planets that were ‘Earth-like’ to some extent, in that most simulations produced one planet with nearly the same mass and semimajor axis as that of the Earth. However, it was found that the initial orbital architecture for the planetary building blocks and giant planets used in the simulations had a dramatic effect on other key properties of the planetary system (O'Brien et al., 2006, Raymond et al., 2009).
Really nice would be the flexibility of customizing specific outcomes, such as 'randomize everything except keep the existence or orbits of Saturn', if I'm interpretating the following correctly:
In the cases where Jupiter and Saturn were assumed to exist on their current orbits, the numbers and masses of the terrestrial planets were more easily reproduced, though the planets tended to accrete very little water-bearing materials from the outer edge of the asteroid belt.
Here we get to the hint, which lacks info on timescales but does confirm that the accretion might be too chaotic to precisely simulate:
Because of the stochastic nature of accretion, it is difficult to evaluate how representative any single run is of the possible accretion histories, and thus final chemical properties, for a resulting planet in a given dynamic scenario. Previous studies performed a small number of N-body simulations, typically four or fewer for each set of initial conditions
Such a small number of runs is understandable as much earlier studies were limited by computational power, while more recent studies concentrated on exploring parameter space instead of running a large number of simulations per set of conditions (Morishima et al., 2010)
(Emphasis mine)
This next
review adds some types of simulated details I'm interested in, the accretion from dust to pebbles to larger objects:
In this Review, we discuss breakthroughs in geochemistry and theoretical modelling that have advanced understanding of Earth accretion. Theory holds that solar nebula dust particles stuck together to form pebbles, concentrations of which gravitationally collapsed into ∼100-km-sized planetesimals, which in turn accreted to yield planets. Isotopic variations in meteorites indicate that pebbles formed within the first 100 kyr of the Solar System, planetesimals melted and differentiated within a few 100 kyr, and Mars accreted quickly within 5 Myr.
Including how planetoids formed in the first few millions of years:
Terrestrial planet accretion commenced with disk grains and high-temperature condensates sticking together to form pebbles, which in turn gravitationally coalesced to form planetesimals up to hundreds of kilometres in size. Planetesimals with metallic cores, sampled today as iron meteorites, were present within the first million years of the Solar System.
And simulating how rock planets form in the inner solar system, including an option to customize an Earth type of collision that could result in a moon:
Planetesimals collided to form Moon-to-Mars-sized planetary embryos in the presence of the solar nebula. Nebular dispersal triggered an era of giant collisions among the embryos that established the inner Solar System’s architecture and, for Earth, culminated in the Giant Impact that produced the Moon.
And finally in this next
activity program by NASA (for kids to mock simulate the formation of a solar system), page 1 says:
As material moved around the protosun, dust grains in the disk collided with each other and started sticking together to form larger rocks. These rocks in turn collided with other rocks and either gravity held them together or they broke into smaller pieces
And farther down it says that meteoroids:
are solid objects traveling around the Sun in a variety of orbits and at various velocities, ranging in size from small pebbles to large boulders
have various compositions and densities, ranging from fragile snowball-like objects to nickel-iron dense rocks
Then says that small asteroids:
are made up of chondrules and other material that holds them together
have many variations, due partly to differences in the number, size, shape, and varying mineral content of the chondrules, and where they were formed in the solar system (close to the hot Sun, far from the Sun?)
While explaining a bit how:
Scientists think that asteroids formed by accretion of these dust particles in the solar nebula, the disk of gas and dust that rotated in a flattish disk shape around the early Sun.
Really interesting that the rocks were forming before the sun started its fusion.
Also chondrules seeming the next step from dust grains, yet they're spherical drops of minerals that were once molten (or partially molten) and how such chondrules are possibly the building blocks of planets.
Definitely would include that in a simulation.
Lastly, the simulation should allow the possibility of gas giants forming.
So, there's what I'm referring to. What's the range of time scales should we anticipate to start a solar system simulation of early accretion and planet formation, and separately, to run such a simulation from the beginning at the solar nebula to our current day types of results?
