[Baps] THURSDAY: T. T. Koskinen (University of Arizona) Saturn atmosphere seminar

[Paul Withers]

-------- Original Message --------
Subject: 	[Announce] THURSDAY: T. T. Koskinen (University of Arizona)
Space Physics Seminar
Date: 	Mon, 17 Mar 2014 13:11:04 +0000
From: 	Grein, Zachary <zgrein at bu.edu>
To: 	announce at skynet.bu.edu <announce at skynet.bu.edu>,
csp_seminar at skynet.bu.edu <csp_seminar at skynet.bu.edu>, iar at skynet.bu.edu
<iar at skynet.bu.edu>



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*BU LOGO***

*Space physics seminar*

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T. T. Koskinen

University of Arizona



*Sunsets on Saturn – a new perspective on the upper atmosphere from 
Cassini UVIS occultations*

*  *

*  *

*Thursday, March 20, 2014*

*725 Commonwealth Ave.*

*Refreshments at 3:30pm in CAS 500*

*Talk begins at 4:00pm in CAS 502*

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*  *

Abstract:

Despite significant advances in our understanding of Saturn’s upper
atmosphere since the Pioneer and Voyager missions, many important
questions remain.  For example, the observed temperatures in the
thermosphere are much higher than expected from solar heating only and
the missing energy source is still unknown.  This problem is common to
all of the giant planets in the solar system, and the solution could
also be relevant to many extrasolar giant planets.  Past studies
indicate that breaking gravity waves, redistribution of auroral energy
by circulation, and electrodynamics may help to explain the high
temperatures.  There are, however, almost no observations available to
directly study such dynamics in the upper atmosphere and only a few
observations of even the density and temperature profiles above the
stratosphere.  In this sense, solar and stellar occultations observed by
Cassini UVIS that probe the atmosphere from the stratosphere to the
exobase provide much needed constraints on the photochemical and
dynamical models.  In particular, the spatial and temporal coverage of
the data potentially allows for the identification of trends indicative
of dynamics and energy deposition.  The analysis of these observations,
however, poses unique challenges that can lead to significant confusion
over their interpretation.  I will review some of these challenges and
present results from more than 20 occultations that map the temperature
and density structure in Saturn’s upper atmosphere.



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