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Brightness and Polarization Phase Curve of Titan

Keywords:

#Titan       #Atmosphere       #Cassini       #Polarimetry

As part of a research project in planetary science, I conducted a detailed observational study of Titan’s atmosphere using image data from the Cassini spacecraft. The goal was to characterize Titan’s reflective and scattering behavior by analyzing brightness and polarization as functions of phase angle. This work combined coding, image processing, and physical modeling to generate phase curves that offer insight into the moon’s atmospheric properties. I developed Python-based tools to extract Titan’s phase geometry and geometric albedo from Cassini/ISS images and used IDL-based scripts to produce and analyze polarimetric data.

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Credit: OPUS

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Credit: OPUS

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Image Processing 

I began by filtering and selecting high-quality Cassini images using the OPUS archive, targeting datasets from the Narrow Angle Camera (NAC) with appropriate filters and polarization configurations. Using Python and libraries like OpenCV, I implemented automated disk detection and calculated Titan’s effective radius for each observation. These masks allowed me to extract accurate reflectance data from images expressed in I/F units and build brightness phase curves normalized to Titan’s radius.

 Filter Comparison

In parallel, I used IDL Virtual Machine scripts (provided by Dr. Robert West) to process polarized image triplets, producing images of Titan’s degree and angle of linear polarization. My analysis focused on NAC filters with polarizer angles at 0°, 60°, and 120°, and generated polarization phase curves for each wavelength band.

Modeling Outlook

These observational results provide a compelling foundation for radiative transfer modeling, which I’m currently pursuing under the guidance of Dr. Theodora Karalidi. By integrating theoretical models using the DAP radiative transfer code with observed phase curves, I aim to constrain Titan’s aerosol properties, including particle size, composition, and vertical distribution. This joint observational-theoretical approach offers a path toward understanding Titan’s complex atmosphere at a deeper level.

This part of the project is still in progress but I will keep updates here.

You can read a more detailed approach and preliminary results in this draft:

And you can access the GitHub here:

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