Custom Atomic Data

Using Your Own Atomic Data

To run a simulation, STARDIS requires an atomic data file that has information on the properties of atoms and molecules needed by STARDIS. While “kurucz_cd23_chianti_H_He.h5” is the default atomic data used by STARDIS, you can create and use other atomic data files by using CARSUS. For more information on using CARSUS you can access the CARSUS documentation.

Relevant CARSUS Data to Collect

While CARSUS accumulates all sorts of data when compiling the atomic data files, not everything it can include is necessary or relevant for running STARDIS. Here is a list of what data/readers you should make sure to include when running CARSUS: - atomic weights & ionization energy from NIST - Robert Kurucz’s Atomic Linelist (GFALL) - atomic and molecular transitions from VALD - Molecular formation from Barklem & Collet 2016

Use CARSUS and follow their documentation to get a data file:

https://tardis-sn.github.io/carsus/

To use new atomic data file in a simulation, add/edit the line in your yaml file atom_data: <path/to/atomic_data>. This path can be either the relative or absolute path. Your atomic data file should have the file extension ‘.h5’.

The file ‘kurucz_cd23_chianti_H_He.h5’ referenced below is the default atomic_data used by STARDIS.

stardis_config_version: 1.0
atom_data: kurucz_cd23_chianti_H_He.h5 # <----- put the relative or absolute path here
model:
...

Using VALD linelists

Possibly one of the most important reasons you would want to use a custom atomic data file would be to take advantage of a tailored VALD linelist. You can refer to VALD’s documentation for information on these lists if you are unfamiliar. To create a detailed and accurate stellar spectrum, we highly recommend looking into using a VALD linelist bundled into your atomic data.

If you have included a VALD linelist in your atom_data file, then you must make the following change to your Yaml file for the linelist to be used:

...
line:
        disable: False
        broadening: [radiation, linear_stark, quadratic_stark, van_der_waals]
        vald_linelist:  #<-----
            use_linelist: True #<----- will default to false, so must set to True
            shortlist: <boolean> #<----- VALD can output lists in 'long' form or 'short' form; set accordingly
no_of_thetas: 20
...