Optical Constants of Titan Haze Analogue from 0.4 to 3.5 {\mu}m: Determined Using Vacuum Spectroscopy

TL;DR

This study determines the optical constants of Titan haze analogues across 0.4 to 3.5 microns using vacuum spectroscopy, aiding atmospheric modeling and remote sensing analysis of Titan.

Contribution

It provides a reliable set of optical constants for Titan haze analogues in the 0.4 to 3.5 micron range, using a novel laboratory spectroscopy method.

Findings

Optical constants of Titan haze analogues were successfully measured.

The method can be extended to other wavelength ranges and planetary analogues.

Results support improved atmospheric and surface modeling of Titan.

Abstract

Titan's thick atmosphere is primarily composed of nitrogen and methane. Complex chemistry happening in Titan's atmosphere produces optically thick organic hazes. These hazes play significant roles in Titan's atmosphere and on its surface, and their optical properties are crucial for understanding many processes happening on Titan. Due to the lack of such information, the optical constants of laboratory prepared Titan haze analogues are essential inputs for atmospheric modeling and data analysis of remote sensing observations of Titan. Here, we perform laboratory simulations in a Titan relevant environment, analyze the resulting Titan haze analogues using vacuum Fourier transform infrared spectroscopy, and calculate the optical constants from the measured transmittance and reflectance spectra. We provide a reliable set of optical constants of Titan haze analogue in the wavelength range from 0.4 to 3.5 micron and will extend to 28.5 micron in the near future, which can both be used for analyzing existing and future observational data of Titan. This study establishes a feasible method to determine optical constants of haze analogues of (exo)planetary bodies.