Glossary

This wiki page is a glossary that provides additional information on various modules/classes/functionalities included in sunbather. We also refer to "Hazy", which is the official documentation of Cloudy and can be found in your $CLOUDY_PATH/docs/ folder.

The tools.py module

This module contains many basic functions and classes that are used by the other sunbather modules, and can also be used when postprocessing/analyzing sunbather output.

This module is not intended to be run from the command line, but rather imported into other scripts in order to use its functions.

The RT.py module

This module contains functions to perform radiative transfer calculations of the planet transmission spectrum.

This module is not intended to be run from the command line, but rather imported into other scripts in order to use its functions.

The construct_parker.py module

This module is used to create Parker wind profiles. The module can make pure H/He profiles, in which case it is basically a wrapper around the p-winds code (dos Santos et al. 2022). The code can however also make Parker wind profiles for an arbitrary composition (e.g. at a given scaled solar metallicity), which is much more computationally expensive, because it then iteratively runs p-winds and Cloudy. In this mode, Cloudy is used to obtain the mean molecular weight structure of the atmosphere for the given composition, which p-winds uses to calculate the density and velocity structure.

This module is intended to be run from the command line while supplying arguments. Running python construct_parker.py --help will give an explanation of each argument.

Example use: python construct_parker.py -plname WASP52b -pdir z_10 -T 8000 -Mdot 11.0 -z 10. This creates a Parker wind profile for the planet WASP52b (must be defined in planets.txt) for a temperature of 8000 K, mass-loss rate of 10^11 g s-1 and a 10x solar metallicity composition, and saves the atmospheric structure as a .txt file in $SUNBATHER_PROJECT_PATH/parker_profiles/WASP52b/z_10/.

The convergeT_parker.py module

This module is used to run Parker wind profiles through Cloudy to (iteratively) solve for a non-isothermal temperature structure. Additionally, the "converged" simulation can then be postprocessed with functionality of the RT.py module in order to make transmission spectra. This module is basically a convenience wrapper which sets up the necessary folder structure and input arguments for the solveT.py module that actually performs the iterative scheme described in Linssen et al. (2022).

This module is intended to be run from the command line while supplying arguments. Running python convergeT_parker.py --help will give an explanation of each argument.

Example use: python convergeT_parker.py -plname HATP11b -pdir fH_0.99 -dir fiducial -T 5000 10000 200 -Mdot 9.0 11.0 0.1 -zelem He=0.1 -cores 4 -save_sp H He Ca+. This simulates Parker wind models with Cloudy for the planet HATP11b (must be defined in planets.txt) for a grid of temperatures between 5000 K and 10000 K in steps of 200 K, mass-loss rates between 10^9 g s-1 and 10^11 g s-1 in steps of 0.1 dex. It looks for the density and velocity structure of these models in the folder $SUNBATHER_PROJECT_PATH/parker_profiles/HATP11b/fH_0.99/ (so these models have to be created first in that folder using construct_parker.py) and saves the Cloudy simulations in the folder $SUNBATHER_PROJECT_PATH/sims/1D/HATP11b/fiducial/. It scales the abundance of helium (which is solar by default in Cloudy, i.e. ~10% by number) by a factor 0.1 so that it becomes 1% by number. 4 different calculations of the $T$-$\dot{M}$-grid are done in parallel, and the atomic hydrogen, helium and singly ionized calcium output are saved by Cloudy, so that afterwards we can use RT.FinFout() to make Halpha, metastable helium and Ca II infrared triplet spectra.

The solveT.py module

This module contains the iterative scheme described in Linssen et al. (2022) to solve for a non-isothermal temperature structure of a given atmospheric profile. It is called by convergeT_parker.py. As long as you're simulating Parker wind profiles (and not some other custom profile), you should be fine using convergeT_parker.py instead of this module.

The $SUNBATHER_PROJECT_PATH (or internally: tools.projectpath) directory

This is the directory on your machine where all Parker wind profiles and Cloudy simulations are saved. You can choose any location and name you like, as long as it doesn't contain any spaces. The full path to this directory must be set as your $SUNBATHER_PROJECT_PATH environmental variable (see installation instructions). The reason sunbather uses a project path is to keep all output from simulations (i.e. user-specific files) separate from the source code.

The planets.txt file

This file stores the bulk parameters of the planets that are simulated. A template of this file is provided in the sunbather base directory, but you must copy it to your $SUNBATHER_PROJECT_PATH in order for it to work. Every time you want to simulate a new planet/star system, you must add a line to this file with its parameters. You can add comments at the end of the line with a # (for example referencing where the values are from). The first column specifies the "name", which is a tag for this system that cannot contain spaces and is used for the -plname argument of construct_parker.py and convergeT_parker.py, as well as for the tools.Planet class to access the system parameters in Python. The second column specifies the "full name", which can be any string you like and can be used e.g. when plotting results. The third column is the radius of the planet in Jupiter radii (7.1492e9 cm). The fourth column is the radius of the star in solar radii (6.9634e10 cm). The fifth column is the semi-major axis of the system in AU (1.49597871e13 cm). The sixth column is the mass of the planet in Jupiter masses (1.898e30 g). The seventh column is the mass of the star in solar masses (1.9891e33 g). The eighth column is the transit impact parameter (dimensionless, 0 is across the center of the stellar disk, 1 is grazing the stellar limb). The ninth column is the name of the stellar SED - see "Stellar SED handling" below in this glossary.

Stellar SED handling

When running sunbather, the spectral energy distribution (SED) of the host star has to be available to Cloudy, which looks for it in its $CLOUDY_PATH/data/SED/ folder. Therefore, every SED you want to use has be copied to that folder, and requires a specific format: the first column must be wavelengths in units of Å and the second column must be the $\lambda F_{\lambda} = \nu F_{\nu}$ flux at a distance of 1 AU in units of erg s-1 cm-2. Additionally, on the first line, after the first flux value, the following keywords must appear: "units angstrom nuFnu". In the /sunbather/stellar_SEDs/ folder, we have provided a few example SEDs in the correct format. Even though Cloudy in principle supports other units, sunbather doesn't, so please stick to the units as described. Normalization of the flux to the planet orbital distance is done automatically by sunbather based on the semi-major axis value given in the planets.txt file.