petitRADTRANS.retrieval.util
This module contains a set of useful functions that don’t really fit anywhere else. This includes flux conversions, prior functions, mean molecular weight calculations, transforms from mass to number fractions, and fits file output.
Module Contents
Functions
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surf_to_meas |
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Get the molecular mass of a given species. |
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calc_MMW |
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wraps calc_MMW |
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Calculate the mean molecular weight from a number fraction |
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Convert mass fractions to number fractions |
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Convert number fractions to mass fractions |
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This function takes in the wavelengths and flux of a model |
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This function uses exo-k to bin the c-k table of a |
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deprecated |
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This function takes in the cloud base pressures for each cloud, |
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Generate a fits file that can be used as an input to a pRT retrieval. |
Attributes
- petitRADTRANS.retrieval.util.SQRT2
- petitRADTRANS.retrieval.util.surf_to_meas(flux, p_rad, dist)
surf_to_meas Convert from emission flux to measured flux at earth Args:
- fluxnumpy.ndarray
Absolute flux value or spectrum as emitted by a source of radius p_rad
- p_radfloat
Planet radius, in same units as dist
- distfloat
Distance to the object, in the same units as p_rad
- Returns:
- m_fluxnumpy.ndarray
Apparent flux
- petitRADTRANS.retrieval.util.freq_to_micron(frequency)
- petitRADTRANS.retrieval.util.fnu_to_flambda(wlen, spectrum)
- petitRADTRANS.retrieval.util.spectrum_cgs_to_si(frequency, spectrum)
- petitRADTRANS.retrieval.util.log_prior(cube, lx1, lx2)
- petitRADTRANS.retrieval.util.uniform_prior(cube, x1, x2)
- petitRADTRANS.retrieval.util.gaussian_prior(cube, mu, sigma)
- petitRADTRANS.retrieval.util.log_gaussian_prior(cube, mu, sigma)
- petitRADTRANS.retrieval.util.delta_prior(cube, x1, x2)
- petitRADTRANS.retrieval.util.inverse_gamma_prior(cube, a, b)
- petitRADTRANS.retrieval.util.b_range(x, b)
- petitRADTRANS.retrieval.util.a_b_range(x, a, b)
- petitRADTRANS.retrieval.util.getMM(species)
Get the molecular mass of a given species.
This function uses the molmass package to calculate the mass number for the standard isotope of an input species. If all_iso is part of the input, it will return the mean molar mass.
- Args:
- speciesstring
The chemical formula of the compound. ie C2H2 or H2O
- Returns:
The molar mass of the compound in atomic mass units.
- petitRADTRANS.retrieval.util.calc_MMW(abundances)
calc_MMW Calculate the mean molecular weight in each layer.
- Args:
- abundancesdict
dictionary of abundance arrays, each array must have the shape of the pressure array used in pRT, and contain the abundance at each layer in the atmosphere.
- petitRADTRANS.retrieval.util.get_MMW_from_mfrac(m_frac)
wraps calc_MMW
- petitRADTRANS.retrieval.util.get_MMW_from_nfrac(n_frac)
Calculate the mean molecular weight from a number fraction
- Args:
- n_fracdict
A dictionary of number fractions
- petitRADTRANS.retrieval.util.mass_to_number(m_frac)
Convert mass fractions to number fractions
- Args:
- m_fracdict
A dictionary of mass fractions
- petitRADTRANS.retrieval.util.number_to_mass(n_fracs)
Convert number fractions to mass fractions
- Args:
- n_fracsdict
A dictionary of number fractions
- petitRADTRANS.retrieval.util.teff_calc(waves, model, dist=1.0, r_pl=1.0)
This function takes in the wavelengths and flux of a model in units of W/m2/micron and calculates the effective temperature by integrating the model and using the stefan boltzmann law. Args:
- wavesnumpy.ndarray
Wavelength grid in units of micron
- modelnumpy.ndarray
Flux density grid in units of W/m2/micron
- distOptional(float)
Distance to the object. Must have same units as r_pl
- r_plOptional(float)
Object radius. Must have same units as dist
- petitRADTRANS.retrieval.util.bin_species_exok(species, resolution)
This function uses exo-k to bin the c-k table of a single species to a desired (lower) spectral resolution.
- Args:
- speciesstring
The name of the species
- resolutionint
The desired spectral resolving power.
- petitRADTRANS.retrieval.util.compute_gravity(parameters)
- petitRADTRANS.retrieval.util.set_resolution(lines, abundances, resolution)
deprecated
- petitRADTRANS.retrieval.util.fixed_length_amr(p_clouds, pressures, scaling=10, width=3)
This function takes in the cloud base pressures for each cloud, and returns an array of pressures with a high resolution mesh in the region where the clouds are located.
Author: Francois Rozet.
- The output length is always
len(pressures[::scaling]) + len(p_clouds) * width * (scaling - 1)
- Args:
- P_cloudsnumpy.ndarray
The cloud base pressures in bar
- pressnp.ndarray
The high resolution pressure array.
- scalingint
The factor by which the low resolution pressure array is scaled
- widthint
The number of low resolution bins to be replaced for each cloud layer.
- petitRADTRANS.retrieval.util.fits_output(wavelength, spectrum, covariance, object, output_dir='', correlation=None)
Generate a fits file that can be used as an input to a pRT retrieval.
- Args:
- wavelengthnumpy.ndarray
The wavelength bin centers in micron. dim(N)
- spectrumnumpy.ndarray
The flux density in W/m2/micron at each wavelength bin. dim(N)
- covariancenumpy.ndarray
The covariance of the flux in (W/m2/micron)^2 dim(N,N)
- objectstring
The name of the object, used for file naming.
- output_dirstring
The parent directory of the output file.
- correlationnumpy.ndarray
The correlation matrix of the flux points (See Brogi & Line 2018, https://arxiv.org/pdf/1811.01681.pdf)
- Returns:
- hdulastropy.fits.HDUlist
The HDUlist object storing the spectrum.