Let's first make sure we have the latest version of PHOEBE 2.2 installed. (You can comment out this line if you don't use pip for your installation or don't want to update to the latest release).
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!pip install -I "phoebe>=2.2,<2.3"
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%matplotlib inline
As always, let's do imports and initialize a logger and a new bundle. See Building a System for more details.
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import phoebe
import numpy as np
b = phoebe.default_binary()
Let's set reasonable (although not necessarily physical) values for the secondary component.
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b.flip_constraint('mass@secondary', solve_for='q')
b.set_value(qualifier='mass', component='secondary', value=0.2)
b.set_value(qualifier='requiv', component='secondary', value=0.2)
b.set_value(qualifier='teff', component='secondary', value=300)
We'll add a spot to the primary component.
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b.add_spot(component='primary',
relteff=0.90,
long=0,
colat=90,
radius=20,
feature='spot01')
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b.add_dataset('lc', compute_times=phoebe.linspace(-0.1, 0.1, 201))
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Because we have such a cool transiting object, we'll have to use blackbody atmospheres and manually provide limb-darkening.
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b.set_value(qualifier='atm', component='secondary', value='blackbody')
b.set_value(qualifier='ld_mode', component='secondary', value='manual')
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anim_times = phoebe.linspace(-0.1, 0.1, 101)
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b.add_dataset('mesh', compute_times=anim_times, coordinates='uvw', columns='teffs')
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b.run_compute(distortion_method='sphere', irrad_method='none')
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print(np.min(b.get_value('teffs', time=0.0, component='primary')), np.max(b.get_value('teffs', time=0.0, component='primary')))
Let's go through these options (see also the plot API docs):
time: make the plot at this single timefc: (will be ignored by everything but the mesh): set the facecolor to the teffs column.fcmap: use 'plasma' colormap instead of the default to avoid whites.fclim: set the limits on facecolor so that the much cooler transiting object doesn't drive the entire range.ec: disable drawing the edges of the triangles in a separate color. We could also set this to 'none', but then we'd be able to "see-through" the triangle edges.tight_layout: use matplotlib's tight layout to ensure we have enough padding between axes to see the labels.
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afig, mplfig = b.plot(time=0.0,
fc='teffs', fcmap='plasma', fclim=(5000, 6000),
ec='face',
tight_layout=True,
show=True)
Now let's animate the same figure in time. We'll use the same arguments as the static plot above, with the following exceptions:
times: pass our array of times that we want the animation to loop over.consider_for_limits: for the mesh panel, keep the primary star centered and allow the transiting object to move in and out of the frame.pad_aspect: pad_aspect doesn't work with animations, so we'll disable to avoid the warning messages.animate: self-explanatory.save: we could use show=True, but that doesn't always play nice with jupyter notebookssave_kwargs: may need to change these for your setup, to create a gif, passing {'writer': 'imagemagick'} is often useful.
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afig, mplfig = b.plot(times=anim_times,
fc='teffs', fcmap='plasma', fclim=(5000, 6000),
ec='face',
consider_for_limits={'primary': True, 'secondary': False},
tight_layout=True, pad_aspect=False,
animate=True,
save='spot_transit.gif',
save_kwargs={'writer': 'imagemagick'})