def z_lambda(sigma_trace,
xi,
p0,
planet_radius,
mass,
T,
planet_mass,
sigma_filler=False):
'''
Parameters
----------
sigma_trace: array
Absorption cross section of atmosphere species as a function of wavelength
p0: float
Reference pressure of atmosphere; pressure at z=0
planet_radius: float
Minimum radius of planet
mass: float
mass of trace atomic species
T: float
Effective temperature of planet
planet_mass: float
mass of the planet in earth masses
Returns
-------
z: float, array
The amount by which the planet's occultation disk is increased by
opacity of the atmosphere, as a function of wavelength.
'''
# convert planet radius to meters
r_p = r_earth * planet_radius
# convert from bars to pa
pressure = p0 * 100000
g = gravity(planet_mass, planet_radius)
h = scale_h(mass, T, g)
if sigma_filler is not None:
# calculate average cross section
sigma = (1 - xi) * sigma_filler + xi * sigma_trace
else:
# set volume mixing ratio to 1
xi = 1
sigma = sigma_trace
# set equiv scale height to 1
tau_eq = 1
# calculate beta
beta = pressure / tau_eq * np.sqrt(2 * np.pi * r_p)
return h * np.log(sigma * 1 / np.sqrt(k * mass * amu_kg * T * g) * beta)
# Grab the initial position/velocity/effort.
(initpos, initvel, initeff) = get_joints()
# Define a command message, which will encode (save) the state of
# the current commands. Start at the current values.
cmdmsg = JointState()
cmdmsg.header.stamp = rospy.Time.now()
cmdmsg.name = fullnames
cmdmsg.position = initpos
cmdmsg.velocity = initvel
cmdmsg.effort = initeff
# Create a publisher to send commands to the robot. Allow initial
# time for the subscriber to connect avoiding any missed commands.
pub = rospy.Publisher('/hebiros/robot/command/joint_state',
JointState, queue_size=10)
rospy.sleep(0.4)
pub.publish(cmdmsg)
# Gradually change the effort to the gravity model.
blocking_rampeffort(pub, cmdmsg, gravity(cmdmsg.position))
# Then move from the current (initial) to the nominal.
blocking_moveto(pub, cmdmsg, [0.4, -0*math.pi/2, 0*math.pi/2], gravity)
# Finally (continually) output the triangle wave.
blocking_trianglewave(pub, cmdmsg, 1, 0.1, 2.0, gravity)