Planet

Function to calculate planet’s orbit and location

planet.orbit_plot(a, e, pa, inc, planet_pos, plot_dpi, res, flip, mode, name='')

Plot the orbit of a planet around a star.

Parameters:

• a (float) – Semi-major axis of the orbit.

• e (float) – Eccentricity of the orbit.

• pa (float) – Position angle of the orbit (degrees).

• inc (float) – Inclination of the orbit (degrees).

• planet_pos (tuple) – Planet’s position (x, y) in the specified mode.

• mode (str) – Coordinate mode (“polar” or “cartesian”).

• name (str) – Additional name for the saved plot file.

• plot_dpi (int) – Dots per inch (DPI) for the plot.

• res (int) – Number of points used for orbit calculations.

Returns:

orbit_*.png

planet.orbit_position(a, e, pa, inc, res)

Calculate the Cartesian positions of points along an elliptical orbit.

Parameters:

• a (float) – Semi-major axis of the orbit.

• e (float) – Eccentricity of the orbit.

• pa (float) – Position angle of the orbit (degrees).

• inc (float) – Inclination of the orbit (degrees).

• res (int) – Number of points used for orbit calculations.

Returns:

Arrays of x and y positions along the orbit.

Return type:

tuple

planet.planet_position(a, e, pa, inc, t, mode, res)

Calculate the position of a planet in an elliptical orbit at a given time.

Parameters:

• a (float) – Semi-major axis of the orbit.

• e (float) – Eccentricity of the orbit.

• pa (float) – Position angle of the orbit (degrees).

• inc (float) – Inclination of the orbit (degrees).

• t (float) – Time value for which to calculate the planet’s position.

• mode (str) – Coordinate mode (“polar” or “cartesian”) for the output.

• res (int) – Number of points used for orbit calculations.

Returns:

Planet’s position in the specified mode.

Return type:

tuple

planet.t_period_convert(t)

Convert a time value to its fractional part in the interval [0, 1].

Parameters:

t (float) – The input time value.

Returns:

The fractional part of the input time.

Return type:

float