This repository provides tables of diffusion timescales for polluted white dwarfs. It also provides tables of surface Ca mass fractions as a function of accretion rate for MESA models accreting bulk earth composition including thermohaline mixing.

The files InterpDiffusion.py and InterpThermohaline.py give examples of interpolating on these tables to map observable parameters to accretion rates. They each provide a log_mdot function for this purpose. These functions take three arguments: surface mass fraction of Ca, Teff, and logg. Here's an example of how to use them in a simple python script:

import InterpThermohaline
import InterpDiffusion

XCa = 1e-6 # surface mass fraction of Calcium
Teff = 11000
logg = 8.1

InterpDiffusion.log_mdot(XCa,Teff,logg)
InterpThermohaline.log_mdot(XCa,Teff,logg)

This will print log10(accretion rate) in units of g/s. The first will assume no thermohaline mixing occurs. The second accounts for thermohaline mixing. In both cases, bulk earth composition is assumed.

You can also use the log_mdots functions for lists or arrays to return a numpy array of accretion rates.

import InterpThermohaline
import InterpDiffusion

XCa = [1e-7, 1e-6, 3e-6]
Teff = [11000, 8000, 14000]
logg = [8.1, 7.8, 8.3]

InterpDiffusion.log_mdots(XCa,Teff,logg)
InterpThermohaline.log_mdots(XCa,Teff,logg)

If you wish to make use of these tables in your work, please cite this paper (and read it too!): http://adsabs.harvard.edu/abs/2019ApJ...872...96B

The file plot.py gives an example of using these interpolation routines to plot accretion rates based on the data from Koester & Wilken (2006, https://www.aanda.org/articles/aa/abs/2006/27/aa4843-06/aa4843-06.html) and Farihi et al. (2012, https://academic.oup.com/mnras/article/424/1/464/1009557).