Lightcurve Animations

import sys
import numpy as np
import matplotlib.pyplot as plt
from IPython.display import HTML

sys.path.append("../..")

from spotgp import (
    TrapezoidSymmetricEnvelope,
    VisibilityFunction,
    SpotEvolutionModel,
    LightcurveModel,
)

np.random.seed(42)

Build a SpotEvolutionModel

A SpotEvolutionModel combines three independent components:

Component	Class	Key parameters
Spot size evolution	TrapezoidSymmetricEnvelope	lspot (plateau [days]), tau_spot (rise/decay [days])
Stellar geometry	VisibilityFunction	peq (equatorial period [days]), kappa (differential rotation), inc (inclination [rad])
Amplitude	SpotEvolutionModel	sigma_k (kernel amplitude), or nspot_rate + alpha_max + fspot

LightcurveModel.from_spot_model additionally accepts:

Parameter	Default	Description
nspot	—	Total number of spots in the simulation
tsim	—	Simulation duration [days]
tsamp	—	Sampling cadence [days]
long	[0, 2π]	Longitude range for spot placement [rad]
lat	from latitude_distribution.lat_range	Latitude range for spot placement [rad]

envelope = TrapezoidSymmetricEnvelope(
    lspot=10.0,      # plateau duration [days]
    tau_spot=5.0,    # rise/decay timescale [days]
)
visibility = VisibilityFunction(
    peq=5.0,         # equatorial rotation period [days]
    kappa=0.3,       # differential rotation shear
    inc=np.pi / 3,   # stellar inclination [rad]
)
model = SpotEvolutionModel(
    envelope=envelope,
    visibility=visibility,
    nspot_rate=0.4,  # spots per day
    alpha_max=0.05,  # peak spot angular radius [rad]
    fspot=0.0,       # spot contrast
)

print("param_keys:", model.param_keys)
print(model)

param_keys: ('peq', 'kappa', 'inc', 'lspot', 'tau_spot', 'sigma_k')
SpotEvolutionModel(
  envelope=TrapezoidSymmetricEnvelope({'lspot': 10.0, 'tau_spot': 5.0}),
  visibility=VisibilityFunction(peq=5.0, kappa=0.3, inc=1.047),
  sigma_k=0.00158113883008419
)

Simulate a lightcurve

lc = LightcurveModel.from_spot_model(
    spot_model=model,
    nspot=20,
    tsim=50,
    tsamp=0.2,
    long=[0, 2 * np.pi],
)

lc.plot_lightcurve()

Create an animation of the star rotation and lightcurve

anim = lc.animate_lightcurve(fps=10, dpi=150, duration=12,
                              outfile="lightcurve_animation.gif",
                              save_last_frame="lightcurve_final_frame.png")
HTML(anim.to_jshtml())

Rendering 120 frames to lightcurve_animation.gif...
Done.
Last frame saved to lightcurve_final_frame.png

Animation size has reached 21108903 bytes, exceeding the limit of 20971520.0. If you're sure you want a larger animation embedded, set the animation.embed_limit rc parameter to a larger value (in MB). This and further frames will be dropped.

Once Loop Reflect