# DAY 4

# Survey!

Please fill out survey HERE to make the course better for future iterations!

NOTE: These are ONLY to help me make the class better, not as a "grade" or anything like that silliness.

# Lecture Notes

#### Day 4 Intro Slides

Reminder of what we have done/some intro to what we are doing today.

# Code/Adventures

## (in increasing complexity, decreasing documentation)

### START HERE!!! Main Adventure (Choose Your Own Adventure #1)

#### Make a fake planetary system in 3D! With some hints about stability.

Python code for solving for a multiplanet system IN THE THIRD DIMENSION.

** Questions: ** (1) Once you have a stable system, how easy is it to disrupt? (2) What sorts of properties of the disrupting body
effect how efficient the disruption is?

#### Choose Your Own Adventure #2

#### Make a planetary system based on Kepler data AND THEN DESTROY IT!

Read in some Kepler data from a confirmed planet system and plot its orbits. Also, throw something at it from the z-axis. See if you can distrupt it.

** Questions: ** (1) What sorts of properties of the disrupting body
effect how efficient the disruption is? (2) Can you disrupt this system with more than 1 body? How do
the parameters of each body effect the disruption?

#### Choose Your Own Adventure #3

#### Plot Solar System Orbits with Rebound

Install the python N-body package "Rebound" and play with the Solar System examples.

** Questions: ** (1) What do the different integrators do? (2) How many extra bodies can you add to your
calculation before it slows down too much? How did this compare to the Hermite solver? Why do you think this is?

#### Choose Your Own Adventure #4

#### Simulate Merging Galaxies with Rebound

Do calculations and plots with the python N-body solver "Rebound" following the merger of two galaxies.

** Questions: ** (1) How different does the final galaxy look depending on how many particles you use?
(2) How does the dynamics change with different integrators?

** IMPORTANT: this code can be taxing on your computer! **

# Resources

#### Indepth Discussion of Several Integrators

Goes over some pros/cons of different sorts of integrators. Hermite integrators are discussed in section 2.3.2.

#### Super Planet Crash!

Can you make a stable system?

#### Bonus: Orbits Game

Can you please your alien overlords by building them awesome planetary systems?

#### A bit about stability of planetary systems

The intro and its equations are the specific points about stability in this paper.

#### A bit more about stability of planetary systems

Figure 1 is just pretty cool in general, and Figure 2 shows the distribution of spacing between planets.

#### Even more about stability of planetary systems

A BUNCH of figures looking at how different parameters of the system effect the stability.