def orbElemsVsRadius(s,rBinEdges,average=False):
"""
Computes the orbital elements for disk particles about a binary system in given radial bins.
Assumes center of mass has v ~ 0
Parameters
----------
s: Tipsy snapshot
rBinEdges: numpy array
Radial bin edges [AU] preferably calculated using binaryUtils.calcDiskRadialBins
average: bool
True -> average over all particles in bin, false -> randomly select 1 particle in bin
Returns
-------
orbElems: numpy array
6 x len(rBinEdges) - 1 containing orbital elements at each radial bin
as e, a, i, Omega, w, nu
"""
#Read snapshot and pull out values of interest
stars = s.stars
gas = s.gas
M = np.sum(stars['mass'])
zero = SimArray(np.zeros(3).reshape((1, 3)),'cm s**-1')
orbElems = np.zeros((6,len(rBinEdges)-1))
#Gas orbiting about system center of mass
com = computeCOM(stars,gas)
#Loop over radial bins calculating orbital elements
for i in range(0,len(rBinEdges)-1):
if average: #Average over all gas particles in subsection
rMask = np.logical_and(gas['rxy'].in_units('au') > rBinEdges[i], gas['rxy'].in_units('au') < rBinEdges[i+1])
if i > 0:
#Include mass of disk interior to given radius
mass = M + np.sum(gas[gas['rxy'] < rBinEdges[i]]['mass'])
else:
mass = M
g = gas[rMask]
N = len(g)
if N > 0:
orbElems[:,i] = np.sum(AddBinary.calcOrbitalElements(g['pos'],com,g['vel'],zero,mass,g['mass']),axis=-1)/N
else: #If there are no particles in the bin, set it as a negative number to mask out later
orbElems[:,i] = -1.0
else: #Randomly select 1 particle in subsection for calculations
rMask = np.logical_and(gas['rxy'].in_units('au') > rBinEdges[i], gas['rxy'].in_units('au') < rBinEdges[i+1])
if i > 0:
mass = M + np.sum(gas[gas['rxy'] < rBinEdges[i]]['mass'])
else:
mass = M
g = gas[rMask]
index = np.random.randint(0,len(g))
particle = g[index]
orbElems[:,i] = AddBinary.calcOrbitalElements(com,particle['pos'],zero,particle['vel'],mass,particle['mass'])
return orbElems
def computeOrbElems(self):
"""
Compute the Kepler orbital elements.
Input: Self (must have r, v set and in proper units)
Output: sets and returns e,a,i,...
"""
# Compute orbital elements from binary center of mass frame Cartesian
# coordinates
assert (self.state != 'Kepler' or self.state != 'kepler'), "Already have orbital elements."
zeroR = SimArray([[0.0, 0.0, 0.0]],'cm')
zeroV = SimArray([[0.0, 0.0, 0.0]],'cm s**-1')
oe = AddBinary.calcOrbitalElements(
self.r,
zeroR,
self.v,
zeroV,
self.m1,
self.m2)
# Set orbital elements, return them as well
self.assignOrbElems(oe)
return oe
def computeOrbElems(self):
"""
Compute the Kepler orbital elements.
Input: Self (must have r, v set and in proper units)
Output: sets and returns e,a,i,...
"""
# Compute orbital elements from binary center of mass frame Cartesian
# coordinates
assert (self.state != 'Kepler' or self.state != 'kepler'), "Already have orbital elements."
zeroR = SimArray([[0.0, 0.0, 0.0]],'cm')
zeroV = SimArray([[0.0, 0.0, 0.0]],'cm s**-1')
oe = AddBinary.calcOrbitalElements(
self.r,
zeroR,
self.v,
zeroV,
self.m1,
self.m2)
# Set orbital elements, return them as well
self.assignOrbElems(oe)
return oe
def orbElemsVsRadius(s, rBinEdges, average=False):
"""
Computes the orbital elements for disk particles about a binary system in given radial bins.
Assumes center of mass has v ~ 0
Parameters
----------
s: Tipsy snapshot
rBinEdges: numpy array
Radial bin edges [AU] preferably calculated using binaryUtils.calcDiskRadialBins
average: bool
True -> average over all particles in bin, false -> randomly select 1 particle in bin
Returns
-------
orbElems: numpy array
6 x len(rBinEdges) - 1 containing orbital elements at each radial bin
as e, a, i, Omega, w, nu
"""
#Read snapshot and pull out values of interest
stars = s.stars
gas = s.gas
M = np.sum(stars['mass'])
zero = SimArray(np.zeros(3).reshape((1, 3)), 'cm s**-1')
orbElems = np.zeros((6, len(rBinEdges) - 1))
#Gas orbiting about system center of mass
com = computeCOM(stars, gas)
#Loop over radial bins calculating orbital elements
for i in range(0, len(rBinEdges) - 1):
if average: #Average over all gas particles in subsection
rMask = np.logical_and(
gas['rxy'].in_units('au') > rBinEdges[i],
gas['rxy'].in_units('au') < rBinEdges[i + 1])
if i > 0:
#Include mass of disk interior to given radius
mass = M + np.sum(gas[gas['rxy'] < rBinEdges[i]]['mass'])
else:
mass = M
g = gas[rMask]
N = len(g)
if N > 0:
orbElems[:, i] = np.sum(AddBinary.calcOrbitalElements(
g['pos'], com, g['vel'], zero, mass, g['mass']),
axis=-1) / N
else: #If there are no particles in the bin, set it as a negative number to mask out later
orbElems[:, i] = -1.0
else: #Randomly select 1 particle in subsection for calculations
rMask = np.logical_and(
gas['rxy'].in_units('au') > rBinEdges[i],
gas['rxy'].in_units('au') < rBinEdges[i + 1])
if i > 0:
mass = M + np.sum(gas[gas['rxy'] < rBinEdges[i]]['mass'])
else:
mass = M
g = gas[rMask]
index = np.random.randint(0, len(g))
particle = g[index]
orbElems[:, i] = AddBinary.calcOrbitalElements(
com, particle['pos'], zero, particle['vel'], mass,
particle['mass'])
return orbElems
