Eclipse depths¶

Although PLATON began life as a transmission spectrum calculator, we have also written an eclipse depth calculator and retriever.

To use the eclipse depth calculator, first create a temperature-pressure profile:

from platon.TP_profile import Profile
p = Profile()
p.set_parametric(1200, 500, 0.5, 0.6, 1e6, 1900)

This creates a parametric T-P profile according to Madhusudhan & Seager 2018. The parameters are: T₀, P₁, α₁, α₂, P₃, T₃. P₀ is set to 10^-4 Pa, while P₂ and T₂ are derived from the six specified parameters.

Then, call the eclipse depth calculator:

from eclipse_depth_calculator import EclipseDepthCalculator

wavelengths, depths = calc.compute_depths(p, Rs, Mp, Rp, Tstar)

Most of the same parameters accepted by the transit depth calculator are also accepted by the eclipse depth calculator.

It is also possible to retrieve on combined transit and eclipse depths:

from platon.combined_retriever import CombinedRetriever

retriever = CombinedRetriever()
fit_info = retriever.get_default_fit_info(Rs, Mp, Rp, T_limb,
               T0=1200, P1=500, alpha1=0.5, alpha2=0.6, P3=1e6, T3=1900)

fit_info.add_uniform_fit_param(...)
fit_info.add_uniform_fit_param(...)

result = retriever.run_multinest(transit_bins, transit_depths, transit_errors,
                                 eclipse_bins, eclipse_depths, eclipse_errors,
                                 fit_info)

Here, T_limb is the temperature at the planetary limb (used for transit depths), while the T-P profile parameters are for the dayside (used for eclipse depths).