ast2000tools.solar_system.SolarSystem¶

class ast2000tools.solar_system.SolarSystem(seed, data_path=None, has_moons=True, verbose=True)¶

Bases: object

Represents a random solar system.

Given an integer seed, a randomized solar system containing a star and multiple planets is generated.

Parameters

seed (int) – The seed to use when generating random solar system properties.
data_path (str, optional) – Specifies the path to the directory where output XML files should be stored (e.g. the MCAst data folder). By default, a folder called “XMLs” is created in the working directory.
has_moons (bool, optional) – Whether the generated planets should be visualized with moons. Setting to False increases performance. Default is True.
verbose (bool, optional) – Whether to print non-essential status messages. Default is True.

Illustration of orbital parameters

Methods

`generate_binary_star_orbit_video`(times, …)	Generates a video of the given trajectories of a planet and two stars that can be played in SSView.
`generate_landing_video`(times, …[, …])	Generates a video of the given lander trajectory that can be played in SSView.
`generate_orbit_video`(times, planet_positions)	Generates a video of the given planet trajectories that can be played in SSView.
`generate_system_snapshot`([filename])	Generates a snapshot of the initial state of the solar system that can be viewed in SSView.
`print_info`()	Prints out info about the solar system.
`verify_planet_positions`(simulation_duration, …)	Verifies that your simulation of the planet trajectories around the star gives a reasonable result.

Attributes

`aphelion_angles`	Array of shape (number_of_planets,) containing the angle between the x-axis and the aphelion direction of each planet, in radians.
`atmospheric_densities`	Array of shape (number_of_planets,) containing the atmospheric density at the surface of each planet, in kilograms per cubic meter.
`data_path`	The path to the directory where output XML files will be stored.
`eccentricities`	Array of shape (number_of_planets,) containing the eccentricity of each planet.
`has_moons`	Whether the generated planets will be visualized with moons.
`initial_orbital_angles`	Array of shape (number_of_planets,) containing the angle between the x-axis and the initial position of each planet, in radians.
`initial_positions`	Array of shape (2, number_of_planets) containing the initial x and y-position of each planet relative to the star, in astronomical units.
`initial_velocities`	Array of shape (2, number_of_planets) containing the initial x and y-velocity of each planet relative to the star, in astronomical units per year.
`masses`	Array of shape (number_of_planets,) containing the mass of each planet in solar masses.
`number_of_planets`	The number of planets in the solar system.
`radii`	Array of shape (number_of_planets,) containing the radius of each planet in kilometers.
`rotational_periods`	Array of shape (number_of_planets,) containing the rotational period of each planet in days.
`seed`	The seed used to generate random solar system properties.
`semi_major_axes`	Array of shape (number_of_planets,) containing the semi-major axis of each planet in astronomical units.
`star_color`	The RGB color of the star.
`star_mass`	The mass of the star in solar masses.
`star_radius`	The radius of the star in kilometers.
`star_temperature`	The surface temperature of the star in kelvin.
`types`	Tuple of length number_of_planets containing strings denoting the type of each planet.
`verbose`	Whether non-essential status messages will be printed.

property seed¶

The seed used to generate random solar system properties.

Type: int

property data_path¶

The path to the directory where output XML files will be stored.

Type: str

property has_moons¶

Whether the generated planets will be visualized with moons.

Type: bool

property verbose¶

Whether non-essential status messages will be printed.

Type: bool

property star_temperature¶

The surface temperature of the star in kelvin.

Type: float

property star_mass¶

The mass of the star in solar masses.

Type: float

property star_radius¶

The radius of the star in kilometers.

Type: float

property star_color¶

The RGB color of the star.

Type: tuple(float)

property number_of_planets¶

The number of planets in the solar system.

Type: int

property semi_major_axes¶

Array of shape (number_of_planets,) containing the semi-major axis of each planet in astronomical units.

Type: 1-D numpy.ndarray

property eccentricities¶

Array of shape (number_of_planets,) containing the eccentricity of each planet.

Type: 1-D numpy.ndarray

property masses¶

Array of shape (number_of_planets,) containing the mass of each planet in solar masses.

Type: 1-D numpy.ndarray

property radii¶

Array of shape (number_of_planets,) containing the radius of each planet in kilometers.

Type: 1-D numpy.ndarray

property initial_orbital_angles¶

Array of shape (number_of_planets,) containing the angle between the x-axis and the initial position of each planet, in radians.

Type: 1-D numpy.ndarray

property aphelion_angles¶

Array of shape (number_of_planets,) containing the angle between the x-axis and the aphelion direction of each planet, in radians.

Type: 1-D numpy.ndarray

property rotational_periods¶

Array of shape (number_of_planets,) containing the rotational period of each planet in days.

Type: 1-D numpy.ndarray

property initial_positions¶

Array of shape (2, number_of_planets) containing the initial x and y-position of each planet relative to the star, in astronomical units.

Type: 2-D numpy.ndarray

property initial_velocities¶

Array of shape (2, number_of_planets) containing the initial x and y-velocity of each planet relative to the star, in astronomical units per year.

Type: 2-D numpy.ndarray

property atmospheric_densities¶

Array of shape (number_of_planets,) containing the atmospheric density at the surface of each planet, in kilograms per cubic meter.

Type: 1-D numpy.ndarray

property types¶

Tuple of length number_of_planets containing strings denoting the type of each planet.

Type: tuple(str)

print_info()¶: Prints out info about the solar system.

verify_planet_positions(simulation_duration, planet_positions, filename=None, number_of_output_points=None)¶

Verifies that your simulation of the planet trajectories around the star gives a reasonable result.

Note

If you get an OSError when the output file is being saved after successful verification, reduce the number of output points by specifying the number_of_output_points argument.

Parameters

simulation_duration (float) – The total duration of the simulation (starting from time zero), in years. Must be at least 20 orbital periods of your home planet.
planet_positions (3-D array_like) – Array of shape (2, number_of_planets, number_of_times) containing the x and y-position of each planet at each time, in astronomical units relative to the star. The positions are assumed to be specified at uniformly spaced times over the simulation duration. The number of times has to be at least 1000.
filename (str, optional) – Specifies the filename/path to save the exact trajectories of the planets to after your trajectories have been verified. They are stored in the binary NumPy .npz format as a dictionary-like object with keys ‘times’ and ‘planet_positions’, The ‘times’ entry is a 1D array of times with length number_of_output_points if this argument was specified, otherwise number_of_times. The ‘planet_positions’ entry is an array of positions with shape (2, number_of_planets, len(times)). By default, no file is generated.
number_of_output_points (int, optional) – The number of exact trajectory points to include in the output .npz file (if applicable). By default, the number of output points will be the same as the number of input points. If your trajectories contain a very large number of points, consider modifying this argument to reduce the output size.

Raises

RuntimeError – When the input positions are too far from the correct positions.

generate_system_snapshot(filename='system_snapshot.xml')¶

Generates a snapshot of the initial state of the solar system that can be viewed in SSView.

Parameters: filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “system_snapshot.xml”.

generate_orbit_video(times, planet_positions, number_of_frames=None, reduce_other_periods=True, filename='orbit_video.xml')¶

Generates a video of the given planet trajectories that can be played in SSView.

Note

The times and positions for the output frames will be sampled uniformly from times and planet_positions.

Parameters

times (1-D array_like) – Array containing the time of each frame in years. Must have a size of at least 100.
planet_positions (3-D array_like) – Array of shape (2, number_of_planets, len(times)) containing the x and y-position of each planet at each time, in astronomical units relative to the star.
number_of_frames (int, optional) – The number of video frames to generate. By default, a suitable number is determined automatically. Must be at least 100 if specified.
reduce_other_periods (bool, optional) – Whether to slow down the rotation of planets that are rotating too fast to be animated properly, and also do the same for the orbits and rotations of moons. Note that the orbital speeds of the planets are not touched. Default is True.
filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “orbit_video.xml”.

generate_binary_star_orbit_video(times, planet_positions, star_1_positions, star_2_positions, number_of_frames=1000, filename='binary_star_video.xml')¶

Generates a video of the given trajectories of a planet and two stars that can be played in SSView.

Note

The times and positions for the output frames will be sampled uniformly from times and the inputted position arrays.

Parameters

times (1-D array_like) – Array containing the time of each frame in years. Must have a size of at least 100.
planet_positions (2-D array_like) – Array of shape (2, len(times)) containing the x and y-position of the planet at each time, in astronomical units relative to the system center.
star_1_positions (2-D array_like) – Array of shape (2, len(times)) containing the x and y-position of star 1 at each time, in astronomical units relative to the system center.
star_2_positions (2-D array_like) – Array of shape (2, len(times)) containing the x and y-position of star 2 at each time, in astronomical units relative to the system center.
number_of_frames (int, optional) – The number of video frames to generate. Default is 1000, but must be at least 100.
filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “binary_star_video.xml”.

generate_landing_video(times, lander_positions, planet_idx, initial_system_time=0, number_of_frames=1000, filename='landing_video.xml')¶

Generates a video of the given lander trajectory that can be played in SSView.

Note

The times and positions for the output frames will be sampled uniformly from times and lander_positions.

Parameters

times (1-D array_like) – Array containing the time of each frame, in seconds since the initial time of the landing sequence. Must have a size of at least 100.
lander_positions (2-D array_like) – Array of shape (2, len(times)) containing the x and y-position of the lander at each time, in meters relative to the destination planet center.
planet_idx (int) – The index of the destination planet.
initial_system_time (float, optional) – The system time when the landing sequence began in years. Default is 0.
number_of_frames (int, optional) – The number of video frames to generate. Default is 1000, but must be at least 100.
filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “landing_video.xml”.