Calendar

Mar
28
Wed
Colloquium PhD Thesis Defense: Ethan Dederick
Mar 28 @ 3:15 pm – 4:15 pm
Colloquium PhD Thesis Defense: Ethan Dederick @ Science Hall 109

Seismic Inferences of Gas Giant Planets: Excitation & Interiors

Ethan Dederick, NMSU

Seismology has been the premier tool of study for understanding the interior structure of the Earth, the Sun, and even other stars. In this thesis we develop the framework for the first ever seismic inversion of a rapidly rotating gas giant planet. We extensively test this framework to ensure that the inversions are robust and operate within a linear regime. This framework is then applied to Saturn to solve for its interior density and sound speed profiles to better constrain its interior structure. This is done by incorporating observations of its mode frequencies derived from Linblad and Vertical Resonances in Saturn’s C-ring. We find that although the accuracy of the inversions is mitigated by the limited number of observed modes, we find that Saturn’s core density must be at least 8.97 +/- 0.01 g cm^{-3} below r/R_S = 0.3352 and its sound speed must be greater than 54.09 +/- 0.01 km s^{-1} below r/R_S = 0.2237. These new constraints can aid the development of accurate equations of state and thus help determine the composition in Saturn’s core. In addition, we investigate mode excitation and whether the \kappa-Mechanism can excite modes on Jupiter. While we find that the \kappa-Mechanism does not play a role in Jovian mode excitation, we discover a different opacity driven mechanism, The Radiative Suppression Mechanism, that can excite modes in hot giant planets orbiting extremely close to their host stars if they receive a stellar flux greater than 10^9~erg cm^{-2} s^{-1}. Finally, we investigate whether moist convection is responsible for exciting Jovian modes. Mode driving can occur if, on average, one cloud column with a 1-km radius exists per 6423 km^2 or if ~43 storms with 200 columns, each with a radius of 25 km, erupt per day. While this seems unlikely given current observations, moist convection does have enough thermal energy to drive Jovian oscillations, should it be available to them.

Aug
20
Tue
Pizza lunch: Nick Arge
Aug 20 @ 12:00 pm – 1:00 pm
Pizza lunch: Nick Arge @ AY 119

Title

Nick Arge, NASA Goddard Space Flight Center

Sep
16
Mon
Pizza lunch: Kristian Finlator
Sep 16 @ 12:30 pm – 1:30 pm
Pizza lunch: Kristian Finlator @ AY 119

Detecting host galaxies of metal absorbers at the end of the dark ages

Sep
30
Mon
Pizza lunch: Jason Jackiewicz
Sep 30 @ 12:30 pm – 1:30 pm
Pizza lunch: Jason Jackiewicz @ AY 119

Current Efforts in Seismology of the Sun and Stars

Oct
14
Mon
Pizza Lunch: Wladimir Lyra
Oct 14 @ 12:30 pm – 1:30 pm
Pizza Lunch: Wladimir Lyra @ AY 119

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Oct
28
Mon
Pizza Lunch: Sultan Hassan
Oct 28 @ 12:30 pm – 1:30 pm
Pizza Lunch: Sultan Hassan @ AY 119

Title

Nov
4
Mon
Pizza lunch: Laurel Farris
Nov 4 @ 12:30 pm – 1:30 pm
Pizza lunch: Laurel Farris @ AY 119

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Nov
11
Mon
Pizza lunch: Moire Prescott
Nov 11 @ 12:30 pm – 1:30 pm
Pizza lunch: Moire Prescott @ AY 119

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Nov
18
Mon
Pizza lunch: Nancy Chanover
Nov 18 @ 12:30 pm – 1:30 pm
Pizza lunch: Nancy Chanover @ AY 119

Title

Dec
2
Mon
Pizza lunch: ASTR 598 (Farhan and Oana)
Dec 2 @ 12:30 pm – 1:30 pm
Pizza lunch: ASTR 598 (Farhan and Oana) @ AY 119

ASTR 598

Farhan Hasan and Oana Vesa