Science Seminars

The Martian Upper Atmosphere as Seen by Imaging Ultraviolet Spectrograph (IUVS) Onboard MAVEN

Speaker: Sonal Jain (LASP)
Date: Thursday, Sep 28, 2017
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

NASA’s MAVEN spacecraft has taken about three earth years (more than one Martian year) of observations of Mars to understand the process of Martian atmospheric evolution. The Imaging Ultraviolet Spectrograph (IUVS) on board MAVEN observes Mars in far and mid ultraviolet (110-340 nm) with unique scanning and pointing capabilities, which are optimized for airglow studies. The ultraviolet airglow emissions observed on Mars are a perfect tracer for the processes occurring in the emitting region of the atmosphere (100-200 km) and provide basic information about atmospheric composition (and its structure), and give insight into the dynamics, energetics, and physics and chemistry of the thermosphere. With its wide spatial and temporal coverage, IUVS observations of Martian UV airglow has contributed immensely to our understanding of the Martian upper atmosphere and its response to incoming solar flux (EUV/FUV) and coupling between lower and upper atmosphere through tides and waves. In this presentation, I will talk about an overview of scientific results obtained by IUVS dayglow measurements, including (1) spatial/temporal distribution of major MUV and FUV emissions and their seasonal variability; (2) the seasonal variation of thermosphere temperatures inferred from dayglow measurements; (3) the effect of solar EUV flux (including the ~27-day solar rotation) and heliocentric distance on upper atmosphere temperature structure (4) Effect of transient events (e.g., flares and dust storms) on the Martian thermosphere.  I will present an overview of these results and their implications for the state of the Martian upper atmosphere.