exo_k.atm
¶
@author: jeremy leconte
Contains classes for atmospheric profiles and their radiative properties. That’s where forward models are computed.
Module Contents¶

class
Atm_profile
(composition={}, psurf=None, ptop=None, logplev=None, tlev=None, Tsurf=None, Tstrat=None, grav=None, Rp=None, Mgas=None, rcp=0.28, Nlev=20)[source]¶ Bases:
object
A class defining an atmospheric PT profile with some global data (gravity, etc.)
The derived class
Atm
handles radiative transfer calculations.Initializes atmospheric profiles
 Parameters
composition (dict) – Keys are molecule names and values the vmr. Vmr can be arrays of size Nlev1 (i.e. the number of layers).
grav (float) – Planet surface gravity (gravity constant with altitude for now).
Rp (float or Astropy.unit quantity) – Planet radius. If float, Jupiter radii are assumed.
rcp (float) – Adiabatic lapse rate for the gas (R/cp)
Mgas (float, optional) – Molar mass of the gas (kg/mol). If given, overrides the molar mass computed from composition.
There are two ways to define the profile. Either define:
Nlev: int Number of level interfaces (Number of layers is Nlev1)
psurf, Tsurf: float Surface pressure (Pa) and temperature
ptop: float Pressure at the top of the model (Pa)
Tstrat: float Stratospheric temperature
or:
logplev: array
tlev: array (same size) These will become the pressures (Pa) and temperatures at the level interfaces. This will be used to define the surface and top pressures. Nlev becomes the size of the arrays.
Warning
Layers are counted from the top down (increasing pressure order). All methods follow the same convention.

set_logPT_profile
(self, log_plev, tlev)[source]¶ Set the logPT profile of the atmosphere with a new one
 Parameters
log_plev (numpy array) – Log pressure (in Pa) at the level surfaces
tlev (numpy array (same size)) – temperature at the level surfaces.

set_adiab_profile
(self, Tsurf=None, Tstrat=None, rcp=0.28)[source]¶ Initializes the logPT atmospheric profile with an adiabat with index R/cp=rcp
 Parameters
Tsurf (float) – Surface temperature.
Tstrat (float, optional) – Temperature of the stratosphere. If None is given, an isothermal atmosphere with T=Tsurf is returned.
rcp (float) – R/c_p of the atmosphere

set_grav
(self, grav=None)[source]¶ Sets the surface gravity of the planet
 Parameters
grav (float) – surface gravity (m/s^2)

set_gas
(self, composition_dict)[source]¶ Sets the composition of the atmosphere
 Parameters
composition_dict (dictionary) – Keys are molecule names, and values are volume mixing ratios. A ‘background’ value means that the gas will be used to fill up to vmr=1 If they do not add up to 1 and there is no background gas_mix, the rest of the gas_mix is considered transparent.
compute_col_dens (boolean, optional) – If True, the column density per layer of the atmosphere is recomputed. This si mostly to save time when we know this will be done later on.

set_Mgas
(self, Mgas=None)[source]¶ Sets the mean molar mass of the atmosphere.
 Parameters
Mgas (float or array of size Nlay) – Mean molar mass (kg/mol). If None is give, the mmm is computed from the composition.

set_rcp
(self, rcp)[source]¶ Sets the adiabatic index of the atmosphere
 Parameters
rcp (float) – R/c_p

set_Rp
(self, Rp)[source]¶ Sets the radius of the planet
 Parameters
Rp (float) – radius of the planet (m)

set_Rstar
(self, Rstar)[source]¶ Sets the radius of the star
 Parameters
Rstar (float) – radius of the star (m)

compute_layer_col_density
(self)[source]¶ Computes the column number density (molecules/m^2) per layer of the atmosphere

compute_altitudes
(self)[source]¶ Compute altitudes of the level surfaces (zlev) and mid layers (zlay).

class
Atm
(k_database=None, cia_database=None, wn_range=None, wl_range=None, **kwargs)[source]¶ Bases:
exo_k.atm.Atm_profile
Class based on Atm_profile that handles radiative trasnfer calculations.
Radiative data are accessed through the
gas_mix.Gas_mix
class.Initialization method that calls Atm_Profile().__init__() and links to Kdatabase and other radiative data.

set_k_database
(self, k_database=None)[source]¶ Change the radiative database used by the
Gas_mix
object handling opacities insideAtm
.See
gas_mix.Gas_mix.set_k_database
for details. Parameters
k_database (
Kdatabase
object) – New Kdatabase to use.

set_cia_database
(self, cia_database=None)[source]¶ Change the CIA database used by the
Gas_mix
object handling opacities insideAtm
.See
gas_mix.Gas_mix.set_cia_database
for details. Parameters
cia_database (
CIAdatabase
object) – New CIAdatabase to use.

set_spectral_range
(self, wn_range=None, wl_range=None)[source]¶ Sets the spectral range in which computations will be done by specifying either the wavenumber (in cm^1) or the wavelength (in micron) range.
See
gas_mix.Gas_mix.set_spectral_range
for details.

opacity
(self, **kwargs)[source]¶ Computes the opacity of each of the layers.
See
gas_mix.Gas_mix.cross_section
for details.

emission_spectrum
(self, integral=True, mu0=0.5, mu_quad_order=None, **kwargs)[source]¶ Returns the emission flux at the top of the atmosphere (in W/m^2/cm^1)
 Parameters
integral (boolean, optional) –
If true, the black body is integrated within each wavenumber bin.
If not, only the central value is used. False is faster and should be ok for small bins, but True is the correct version.
 Other Parameters
mu0 (float) – Cosine of the quadrature angle use to compute output flux
mu_quad_order (int) – If an integer is given, the emission intensity is computed for a number of angles and integrated following a gauss legendre quadrature rule of order mu_quad_order.
 Returns
A spectrum with the Spectral flux at the top of the atmosphere (in W/m^2/cm^1)
 Return type
Spectrum object

emission_spectrum_quad
(self, integral=True, mu_quad_order=3, **kwargs)[source]¶ Returns the emission flux at the top of the atmosphere (in W/m^2/cm^1) using gauss legendre qudrature of order mu_quad_order
 Parameters
integral (boolean, optional) –
If true, the black body is integrated within each wavenumber bin.
If not, only the central value is used. False is faster and should be ok for small bins, but True is the correct version.
 Returns
A spectrum with the Spectral flux at the top of the atmosphere (in W/m^2/cm^1)
 Return type
Spectrum object

surf_bb
(self, integral=True)[source]¶ Computes the surface black body flux (in W/m^2/cm^1)
 Parameters
integral (boolean, optional) –
If true, the black body is integrated within each wavenumber bin.
If not, only the central value is used. False is faster and should be ok for small bins, but True is the correct version.
 Returns
Spectral flux at the surface (in W/m^2/cm^1)
 Return type
Spectrum object

top_bb
(self, integral=True)[source]¶ Computes the top of atmosphere black body flux (in W/m^2/cm^1)
 Parameters
integral (boolean, optional) –
If true, the black body is integrated within each wavenumber bin. If not, only the central value is used.
False is faster and should be ok for small bins, but True is the correct version.
 Returns
Spectral flux of a bb at the temperature at the top of atmosphere (in W/m^2/cm^1)
 Return type
Spectrum object

transmittance_profile
(self, **kwargs)[source]¶ Computes the transmittance profile of an atmosphere, i.e. Exp(tau) for each layer of the model. Real work done in the numbafied function path_integral_corrk/xsec depending on the type of data.

transmission_spectrum
(self, normalized=False, Rstar=None, **kwargs)[source]¶ Computes the transmission spectrum of the atmosphere. In general (see options below), the code returns the transit depth:
delta_nu=(pi*Rp^2+alpha_nu)/(pi*Rstar^2).
where
alpha_nu=2*pi*Int_0^zmax (Rp+z)*(1exp(tau_nu(z))) dz
 Parameters
Rstar (float, optional) – Radius of the host star. Does not need to be given here if as already been specified as an attribute of the self.Atm object. If specified, the result is the transit depth: delta_nu=(pi*Rp^2+alpha_nu)/(pi*Rstar^2).
normalized (boolean, optional) –
Used only if self.Rstar and Rstar are None. * If true, the result is normalized to the planetary radius:
delta_nu=1+alpha_nu/(pi*Rp^2).
If False, delta_sigma=1+(h_sigma/R_planet)^2. delta_nu=pi*Rp^2+alpha_nu.
 Returns
The transit spectrum (see above for normalization options).
 Return type
array

heating_rate
(self, Fin=1.0, Tstar=5570.0, szangle=60.0, **kwargs)[source]¶ Computes the heating rate in the atmosphere
 Parameters
Fin (float) – Bolometric stellar flux at the top of atmopshere (W/m^2).
Tstar (float) – Stellar temperature
szangle (float) – Solar zenith angle
 Returns
Heating rate in each atmospheric layer (K/s).
 Return type
array

emission_spectrum_exp_integral
(self, integral=True, **kwargs)[source]¶ Computes the emission flux at the top of the atmosphere (in W/m^2/cm^1)
Warning
This method uses a formulation with exponential integrals that is not yet perceived as accurate enough by the author. It is left for testing only.
 Parameters
integral (boolean, optional) –
If true, the black body is integrated within each wavenumber bin.
If not, only the central value is used. False is faster and should be ok for small bins, but True is the correct version.
 Returns
A spectrum with the Spectral flux at the top of the atmosphere (in W/m^2/cm^1)
 Return type
Spectrum object
