STUDY OF TITAN’S SEASONAL VARIATION IN HYDROGEN CYANIDE (HCN) EFFECTS USING ALMA DURING THE PERIOD 2012-2016

• Main Author: Az Zahra, Maulidiani
• Format: Theses
• Language: Indonesia
• Subjects: Karya Umum
• Online Access: https://digilib.itb.ac.id/gdl/view/70384
• Institution: Institut Teknologi Bandung

Titan is the only satellite in the Solar System known to have a thick atmosphere. The main components of Titan’s atmosphere, namely nitrogen and methane, undergo photochemical processes and produce various hydrocarbon compounds, nitriles, and haze particles. The highest abundance of nitrile compounds produced is hydrogen cyanide (HCN). In addition to playing an important role in the cooling mechanism of Titan’s upper atmosphere, HCN also has a longer chemical lifetime than the dynamic time scale of Titan’s stratosphere, making it possible to serve as a tracer species in viewing Titan’s global circulation. In addition, various observations also indicate that there are variations in the abundance of HCN according to seasonal changes. Through the Cassini-Huygens mission, chemical compositions of Titan’s atmosphere, including HCN, are mapped and monitored over time. HCN has also been observed through ground-based observations in the era before and after the Cassini mission, including at radio wavelengths. One of the most recent groundbased observations at radio wavelengths uses the Atacama Large Millimeter/submillimeter Array (ALMA). With a maximum resolution of up to tens of milliseconds of arc, ALMA can be used to study the spatial variations of various compounds in Titan’s atmosphere. ALMA observations, which often involve Titan as a flux calibrator, allow observational data to be collected without going through a specific observation program. In this study, the ALMA data were used to derive HCN abundance profiles from three spatial areas during the 2012-2016 period. Furthermore, changes occurring during mid-spring to summer in Titan’s northern hemisphere, in accordance with the availability of ALMA observational data, namely toward the end of the Cassini mission in September 2017 are specifically studied. Continuous observations of seasonal variations in tracer atmospheric compounds are essential to understanding the interactions between the chemical processes, radiation, and dynamics that occur in Titan’s atmosphere.