TY - JOUR
T1 - The Evolution of Hydrocarbon Compounds in Saturn's Stratosphere During the 2010 Northern Storm
AU - Hesman, B. E.
AU - Bjoraker, G. L.
AU - Achterberg, R. K.
AU - Sada, P. V.
AU - Jennings, D. E.
AU - Lunsford, A. W.
AU - Sinclair, J.
AU - Romani, P. N.
AU - Boyle, R.
AU - Fletcher, L. N.
AU - Irwin, P.
PY - 2013/12/1
Y1 - 2013/12/1
N2 - The massive eruption at 40N (planetographic latitude) in December 2010
has produced significant and long-lived changes in temperature and
species abundances in Saturn's northern hemisphere (Hesman et al. 2012a,
Fletcher et al. 2012). The northern storm region has been observed on
many occasions between January 2011 and June of 2012 by Cassini's
Composite Infrared Spectrometer (CIRS). In this time period,
temperatures in regions referred to as 'beacons' (warm regions in the
stratosphere at certain longitudes in the storm latitude) became
significantly warmer than pre-storm values of 140K. In this period
hydrocarbon emission greatly increased; however, this increased emission
could not be attributed due to the temperature changes alone for many of
these species (Hesman et al. 2012b, Bjoraker et al 2012). The unique
nature of the stratospheric beacons also resulted in the detection of
ethylene (C2H4) using CIRS. These beacon regions
have also led to the identification of rare hydrocarbon species such as
C4H2 and C3H4 in the
stratosphere. These species are all expected from photochemical
processes in the stratosphere, however high temperatures, unusual
chemistry, or dynamics are enhancing these species. The exact cause of
these enhancements is still under investigation. Ground-based
observations were performed using the high-resolution spectrometer
Celeste in May 2011 to confirm the CIRS detection of
C2H4 and to study its spectral signatures at
higher spectral resolution. In order to follow the evolution of its
emission further observations were performed in July 2011 and March
2012. These observations are being used in conjunction with the CIRS
observations to investigate the source of the approximately 100-fold
increase of ethylene in the stratospheric beacon. The time evolution of
hydrocarbon emission from C2H2,
C2H4, C2H6,
C3H4, and C4H2 in Saturn's
Northern Storm beacon regions will be discussed. References: Bjoraker,
G., B.E. Hesman, R.K. Achterberg, P.N. Romani. 2012, 'The Evolution of
Hydrocarbons in Saturn's Northern Storm Region,' AAS DPS Conference,
Vol. 44, #403.05. Fletcher, L.N. et al. 2012, 'The Origin and Evolution
of Saturn's 2011-2012 Stratospheric Vortex,' Icarus, 221, 560-586.
Hesman, B.E. et al. 2012a, 'Elusive Ethylene Detected in Saturn's
Northern Storm Region,' The Astrophysical Journal, 760, 24-30. Hesman,
B.E. et al. 2012b, 'Ethylene Emission in the Aftermath of Saturn's 2010
Northern Storm,' AAS DPS Conference, Vol. 44, #403.06.
AB - The massive eruption at 40N (planetographic latitude) in December 2010
has produced significant and long-lived changes in temperature and
species abundances in Saturn's northern hemisphere (Hesman et al. 2012a,
Fletcher et al. 2012). The northern storm region has been observed on
many occasions between January 2011 and June of 2012 by Cassini's
Composite Infrared Spectrometer (CIRS). In this time period,
temperatures in regions referred to as 'beacons' (warm regions in the
stratosphere at certain longitudes in the storm latitude) became
significantly warmer than pre-storm values of 140K. In this period
hydrocarbon emission greatly increased; however, this increased emission
could not be attributed due to the temperature changes alone for many of
these species (Hesman et al. 2012b, Bjoraker et al 2012). The unique
nature of the stratospheric beacons also resulted in the detection of
ethylene (C2H4) using CIRS. These beacon regions
have also led to the identification of rare hydrocarbon species such as
C4H2 and C3H4 in the
stratosphere. These species are all expected from photochemical
processes in the stratosphere, however high temperatures, unusual
chemistry, or dynamics are enhancing these species. The exact cause of
these enhancements is still under investigation. Ground-based
observations were performed using the high-resolution spectrometer
Celeste in May 2011 to confirm the CIRS detection of
C2H4 and to study its spectral signatures at
higher spectral resolution. In order to follow the evolution of its
emission further observations were performed in July 2011 and March
2012. These observations are being used in conjunction with the CIRS
observations to investigate the source of the approximately 100-fold
increase of ethylene in the stratospheric beacon. The time evolution of
hydrocarbon emission from C2H2,
C2H4, C2H6,
C3H4, and C4H2 in Saturn's
Northern Storm beacon regions will be discussed. References: Bjoraker,
G., B.E. Hesman, R.K. Achterberg, P.N. Romani. 2012, 'The Evolution of
Hydrocarbons in Saturn's Northern Storm Region,' AAS DPS Conference,
Vol. 44, #403.05. Fletcher, L.N. et al. 2012, 'The Origin and Evolution
of Saturn's 2011-2012 Stratospheric Vortex,' Icarus, 221, 560-586.
Hesman, B.E. et al. 2012a, 'Elusive Ethylene Detected in Saturn's
Northern Storm Region,' The Astrophysical Journal, 760, 24-30. Hesman,
B.E. et al. 2012b, 'Ethylene Emission in the Aftermath of Saturn's 2010
Northern Storm,' AAS DPS Conference, Vol. 44, #403.06.
M3 - Article
VL - 21
JO - American Geophysical Union, Fall Meeting 2013
JF - American Geophysical Union, Fall Meeting 2013
ER -