Minimal Contact Binary System

Setup

Let's first make sure we have the latest version of PHOEBE 2.0 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).



In [ ]:

    
!pip install -I "phoebe>=2.0,<2.1"

As always, let's do imports and initialize a logger and a new bundle. See Building a System for more details.



In [1]:

    
%matplotlib inline



In [2]:

    
import phoebe
from phoebe import u # units
import numpy as np
import matplotlib.pyplot as plt

logger = phoebe.logger()









    



/usr/local/lib/python2.7/dist-packages/IPython/kernel/__init__.py:13: ShimWarning: The `IPython.kernel` package has been deprecated. You should import from ipykernel or jupyter_client instead.
  "You should import from ipykernel or jupyter_client instead.", ShimWarning)
WARNING: Constant u'Gravitational constant' is already has a definition in the u'si' system [astropy.constants.constant]
WARNING:astropy:Constant u'Gravitational constant' is already has a definition in the u'si' system
WARNING: Constant u'Solar mass' is already has a definition in the u'si' system [astropy.constants.constant]
WARNING:astropy:Constant u'Solar mass' is already has a definition in the u'si' system
WARNING: Constant u'Solar radius' is already has a definition in the u'si' system [astropy.constants.constant]
WARNING:astropy:Constant u'Solar radius' is already has a definition in the u'si' system
WARNING: Constant u'Solar luminosity' is already has a definition in the u'si' system [astropy.constants.constant]
WARNING:astropy:Constant u'Solar luminosity' is already has a definition in the u'si' system

Here we'll initialize a default binary, but ask for it to be created as an overcontact



In [3]:

    
b_cb = phoebe.default_binary(contact_binary=True)









    



/usr/local/lib/python2.7/dist-packages/astropy/units/quantity.py:732: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  return super(Quantity, self).__eq__(other)

We'll compare this to the default detached binary



In [4]:

    
b_detached = phoebe.default_binary()

Hierarchy

Let's first look at the hierarchy of the default detached binary, and then compare that to the hierarchy of the overcontact system



In [5]:

    
print b_detached.hierarchy









    



    orbit:binary 
    
        star:primary 
        star:secondary



In [6]:

    
print b_cb.hierarchy









    



    orbit:binary 
    
        star:primary 
        star:secondary 
        envelope:contact_envelope

As you can see, the overcontact system has an additional "component" with method "envelope" and component label "contact_envelope".

Next let's look at the parameters in this envelope component



In [7]:

    
print b_cb.filter(component='contact_envelope', kind='envelope', context='component')









    



ParameterSet: 9 parameters
  abun@contact_envelope@compo...: 0.0
  pot@contact_envelope@component: 3.5
  intens_coeff1@contact_envel...: 1.0
  intens_coeff2@contact_envel...: 1.0
  intens_coeff3@contact_envel...: 1.0
  intens_coeff4@contact_envel...: 1.0
  intens_coeff5@contact_envel...: 1.0
  ld_func_bol@contact_envelop...: logarithmic
  ld_coeffs_bol@contact_envel...: [ 0.5  0.5]



In [8]:

    
b_cb['pot@contact_envelope'] = 3.5



In [9]:

    
b_cb['pot@contact_envelope']









    Out[9]:





<Parameter: pot=3.5 | keys: description, value, quantity, default_unit, limits, visible_if, copy_for>

The individual stars are still there, but since the surface is being defined by the contact envelope, most of the parameters are no longer relevant.



In [10]:

    
print b_cb.filter(component='primary', kind='star', context='component')









    



ParameterSet: 8 parameters
          teff@primary@component: 6000.0 K
     gravb_bol@primary@component: 0.32
  irrad_frac_refl_bol@primary...: 0.6
* irrad_frac_lost_bol@primary...: 0.4
   ld_func_bol@primary@component: logarithmic
  ld_coeffs_bol@primary@compo...: [ 0.5  0.5]
*         mass@primary@component: 0.998813135806 solMass
*          sma@primary@component: 2.65 solRad

Now, of course, if we didn't originally know we wanted a contact binary and built the default detached system, we could still turn it into an contact binary just by changing the hierarchy.



In [11]:

    
b_detached.add_component('envelope', component='contact_envelope')









    Out[11]:





<ParameterSet: 9 parameters | qualifiers: abun, pot, ld_func_bol, ld_coeffs_bol, intens_coeff1, intens_coeff2, intens_coeff3, intens_coeff4, intens_coeff5>



In [12]:

    
hier = phoebe.hierarchy.binaryorbit(b_detached['binary'], b_detached['primary'], b_detached['secondary'], b_detached['contact_envelope'])
print hier









    



orbit:binary(star:primary, star:secondary, envelope:contact_envelope)



In [13]:

    
b_detached.set_hierarchy(hier)



In [14]:

    
print b_detached.hierarchy









    



    orbit:binary 
    
        star:primary 
        star:secondary 
        envelope:contact_envelope

Likewise, we can make a contact system detached again simply by removing the envelope from the hierarchy. The parameters themselves will still exist (unless you remove them), so you can always just change the hierarchy again to change back to an overcontact system.



In [15]:

    
hier = phoebe.hierarchy.binaryorbit(b_detached['binary'], b_detached['primary'], b_detached['secondary'])
print hier









    



orbit:binary(star:primary, star:secondary)



In [16]:

    
b_detached.set_hierarchy(hier)



In [17]:

    
print b_detached.hierarchy









    



    orbit:binary 
    
        star:primary 
        star:secondary

Adding Datasets



In [18]:

    
b_cb.add_dataset('mesh', times=[0], dataset='mesh01')









    Out[18]:





<ParameterSet: 2 parameters | contexts: compute, dataset>



In [19]:

    
b_cb.add_dataset('orb', times=np.linspace(0,3,201), dataset='orb01')









    Out[19]:





<ParameterSet: 3 parameters | contexts: compute, dataset>



In [20]:

    
b_cb.add_dataset('lc', times=np.linspace(0,3,21), dataset='lc01')









    Out[20]:





<ParameterSet: 16 parameters | contexts: compute, dataset>



In [21]:

    
b_cb.add_dataset('rv', times=np.linspace(0,3,21), dataset='rv01')









    Out[21]:





<ParameterSet: 16 parameters | contexts: compute, dataset>

For comparison, we'll do the same to our detached system



In [22]:

    
b_detached.add_dataset('mesh', times=[0], dataset='mesh01')









    Out[22]:





<ParameterSet: 2 parameters | contexts: compute, dataset>



In [23]:

    
b_detached.add_dataset('orb', times=np.linspace(0,3,201), dataset='orb01')









    Out[23]:





<ParameterSet: 3 parameters | contexts: compute, dataset>



In [24]:

    
b_detached.add_dataset('lc', times=np.linspace(0,3,21), dataset='lc01')









    Out[24]:





<ParameterSet: 16 parameters | contexts: compute, dataset>



In [25]:

    
b_detached.add_dataset('rv', times=np.linspace(0,3,21), dataset='rv01')









    Out[25]:





<ParameterSet: 16 parameters | contexts: compute, dataset>

Running Compute



In [26]:

    
b_cb.run_compute(irrad_method='none')









    Out[26]:





<ParameterSet: 64 parameters | kinds: rv, mesh, orb, lc>



In [27]:

    
b_detached.run_compute(irrad_method='none')









    Out[27]:





<ParameterSet: 108 parameters | kinds: rv, mesh, orb, lc>

Synthetics

The synthetic meshes for our overcontact system are attached to the envelope component, whereas the detached system are attached to the two star components



In [28]:

    
print b_cb['mesh01@model'].components









    



['contact_envelope']



In [29]:

    
print b_detached['mesh01@model'].components









    



['primary', 'secondary']

But dynamical quantities are still attached for each star component - regardless of whether they're in a detached or overcontact system



In [30]:

    
print b_cb['orb01@model'].components









    



['primary', 'secondary']



In [31]:

    
print b_detached['orb01@model'].components









    



['primary', 'secondary']

Plotting

Meshes



In [32]:

    
axs, artists = b_cb['mesh01@model'].plot(x='zs')



In [33]:

    
axs, artists = b_detached['mesh01@model'].plot(x='zs')

Orbits



In [34]:

    
axs, artists = b_cb['orb01@model'].plot()



In [35]:

    
axs, artists = b_detached['orb01@model'].plot()

Light Curves



In [36]:

    
axs, artists = b_cb['lc01@model'].plot()



In [37]:

    
axs, artists = b_detached['lc01@model'].plot()

RVs



In [38]:

    
axs, artists = b_cb['rv01@model'].plot()



In [39]:

    
axs, artists = b_detached['rv01@model'].plot()



In [ ]: