PHOEBE 2.1 Documentation

2.1 Docs

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Minimal Contact Binary System¶

Setup¶

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

%matplotlib inline

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

logger = phoebe.logger()


Here we’ll initialize a default binary, but ask for it to be created as a contact system.

b_cb = phoebe.default_binary(contact_binary=True)


We’ll compare this to the default detached binary

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

print b_detached.hierarchy

orbit:binary

star:primary
star:secondary

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 the envelope and star components. You can see that most of parameters in the envelope class are constrained, while the equivalent radius of the primary is unconstrained. The value of primary equivalent radius constrains the potential and fillout factor of the envelope, as well as the equivalent radius of the secondary.

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

ParameterSet: 5 parameters
abun@contact_envelope@compo...: 0.0
* fillout_factor@contact_enve...: 0.641789708077
* pot@contact_envelope@component: 3.40137740723
* pot_min@contact_envelope@co...: 3.20679622409
* pot_max@contact_envelope@co...: 3.75

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

ParameterSet: 18 parameters
teff@primary@component: 6000.0 K
syncpar@primary@component: 1.0
*       period@primary@component: 0.5 d
*         freq@primary@component: 12.56637 rad / d
pitch@primary@component: 0.0 deg
yaw@primary@component: 0.0 deg
incl@primary@component: 90.0 deg
long_an@primary@component: 0.0 deg
gravb_bol@primary@component: 0.32
ld_func_bol@primary@component: logarithmic
ld_coeffs_bol@primary@compo...: [0.5 0.5]
*         mass@primary@component: 1.00890679945 solMass

b_cb['requiv@primary'] = 1.5

b_cb['pot@contact_envelope@component']

<Parameter: pot=3.40137740723 | keys: description, value, quantity, default_unit, limits, visible_if, copy_for>

b_cb['fillout_factor@contact_envelope@component']

<Parameter: fillout_factor=0.641789708077 | keys: description, value, quantity, default_unit, limits, visible_if, copy_for>

b_cb['requiv@secondary@component']

<Parameter: requiv=1.5 solRad | keys: description, value, quantity, default_unit, limits, visible_if, copy_for>


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.

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

<ParameterSet: 5 parameters | qualifiers: abun, pot_max, pot, fillout_factor, pot_min>

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)

b_detached.set_hierarchy(hier)

Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING secondary is overflowing at L2/L3 (requiv=nan, requiv_max=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.
Fri, 26 Oct 2018 11:41 PARAMETERS   WARNING primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)  If not addressed, this warning will continue to be raised and will throw an error at run_compute.

print b_detached.hierarchy

orbit:binary

star:primary
star:secondary
envelope:contact_envelope


However, since our system was detached, the system is not overflowing, and therefore doesn’t pass system checks

b_detached.run_checks()

(False,
'primary is underflowing at L1 and not a contact system (requiv=1.0, requiv_min=2.01327517654)')


And because of this, the potential and requiv@secondary constraints cannot be computed

b_detached['pot@component']

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

b_detached['requiv@secondary@component']

<Parameter: requiv=nan solRad | keys: description, value, quantity, default_unit, limits, visible_if, copy_for>


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.

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

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

b_detached.set_hierarchy(hier)

print b_detached.hierarchy

orbit:binary

star:primary
star:secondary


Although the constraints have been removed, PHOEBE has lost the original value of the secondary radius (because of the failed contact constraints), so we’ll have to reset that here as well.

b_detached['requiv@secondary'] = 1.0


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

<ParameterSet: 4 parameters | contexts: compute, dataset>

b_cb.add_dataset('orb', times=np.linspace(0,1,201), dataset='orb01')

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

b_cb.add_dataset('lc', times=np.linspace(0,1,21), dataset='lc01')

<ParameterSet: 15 parameters | contexts: compute, dataset>

b_cb.add_dataset('rv', times=np.linspace(0,1,21), dataset='rv01')

<ParameterSet: 15 parameters | contexts: compute, dataset>


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

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

<ParameterSet: 4 parameters | contexts: compute, dataset>

b_detached.add_dataset('orb', times=np.linspace(0,1,201), dataset='orb01')

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

b_detached.add_dataset('lc', times=np.linspace(0,1,21), dataset='lc01')

<ParameterSet: 15 parameters | contexts: compute, dataset>

b_detached.add_dataset('rv', times=np.linspace(0,1,21), dataset='rv01')

<ParameterSet: 15 parameters | contexts: compute, dataset>


Running Compute¶

b_cb.run_compute(irrad_method='none')

<ParameterSet: 26 parameters | kinds: rv, mesh, orb, lc>

b_detached.run_compute(irrad_method='none')

<ParameterSet: 26 parameters | kinds: rv, mesh, orb, lc>


Synthetics¶

To ensure compatibility with computing synthetics in detached and semi-detached systems in Phoebe, the synthetic meshes for our overcontact system are attached to each component separetely, instead of the contact envelope.

print b_cb['mesh01@model'].components

['primary', 'secondary']

print b_detached['mesh01@model'].components

['primary', 'secondary']


Plotting¶

Meshes¶

afig, mplfig = b_cb['mesh01@model'].plot(x='ws', show=True)

afig, mplfig = b_detached['mesh01@model'].plot(x='ws', show=True)


Orbits¶

afig, mplfig = b_cb['orb01@model'].plot(x='ws',show=True)

afig, mplfig = b_detached['orb01@model'].plot(x='ws',show=True)


Light Curves¶

afig, mplfig = b_cb['lc01@model'].plot(show=True)

afig, mplfig = b_detached['lc01@model'].plot(show=True)


RVs¶

afig, mplfig = b_cb['rv01@model'].plot(show=True)

afig, mplfig = b_detached['rv01@model'].plot(show=True)

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Last update: 10/29/2018 9:20 a.m. (CET)