Ethan Dederick » Graduate Students

Ethan Dederick

Graduate Student NMSUAstronomy

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Biographical Info


I completed a Bachelor of Arts degree in physics and astronomy in 2014 at Whitman College and a Master of Science in astronomy at New Mexico State University in 2016. My expected graduation date for my Ph.D in theoretical astrophysics is May 2018.

My thesis involves constraining the interior structure of Saturn by using seismic techniques. The oscillations of Saturn perturb its gravitational field. Those repetitive perturbations can induce gaps in Saturn’s rings. Where the gaps occur and what the structure of the gaps are tell us what frequencies Saturn is oscillating at and what spherical harmonics might correspond to those frequencies. We can then use that information coupled with theoretical models of Saturn to perform seismic inversions. These inversions are what allow us to determine just how accurate the state variables of our model are (things like the density profile, sound speed profile, etc.).

In addition, I investigate what excites the global oscillations of Jupiter, Saturn, and Hot Jupiters. For potential driving mechanisms on Jupiter, I’m primarily looking at moist convection in the upper Jovian atmosphere as well as a modified Kappa mechanism. I found that the Kappa mechanism cannot be responsible for Jovian oscillations, but in the process I discovered a new mechanism that can potentially excite oscillations in Hot Jupiters, called the Radiative Suppression Mechanism (see publications).

I also contribute to the JIVE (Jovian Interior with Velocimetry Experiment) and JOVIAL (Jovian Oscillations through radial Velocimetry ImAging observations at several Longitudes) teams. We are working with NASA, New Mexico Tech, and Observatoire de la Cote d’Azur in Nice, France. The mission is to design and build a spectrograph (Doppler spectro-imager based on a Mach-Zender Interferometer) capable of observing the oscillations of Jupiter and Saturn to get frequency and amplitude data on Jovian oscillations to better understand their interiors and atmospheres, particularly their core masses and sizes to constrain planetary formation theories. The instrument will be mounted at the Apache Point 1-meter telescope and observations should begin in 2017.

I’m also one of 100 Mars One astronaut candidates for the first manned mission to Mars. Look up Mars One for more information.

I have worked as a member of the star-disk evolution modeling group at Whitman College. I studied the density modes (J, P, I, and edge) that evolve in stellar disks revolving around resolved stars caused by coupling with density structures inside the stars. I created hydrostatic fluid simulations in both linear and non-linear regions using Legacy Code, and discovered early evolution of edge modes (spiraling density structures near the outer disk edges) when star and disk were separated by relatively short distances. I am curious to understand how current models can become unreliable when the disk and star collide and how to better model star and disk merging, including the effects of evolution on density structures in the disk.

My undergraduate honors thesis at Whitman College consisted of studying prestellar cores in the Cepheus Flare star forming region as imaged by the Herschel Space Telescope. I determined Sersic profiles for the cores and statistically analyzed them for theorists to better constrain their star evolution models.

I worked with Dr. Mark Beck at Whitman College on a project involving quantum state tomography of entangled-photon pairs. When one performs a measurement on one photon of an entangled pair the quantum state of the other photon should change, with the precise state of the second photon depending on the results of the measurement performed on the first photon. We devised and implemented an experiment to measure the quantum mechanical polarization state of one member of such pairs (as described by the density matrix). We demonstrated that if the two photons were in a non-entangled state then the state of one photon would be independent of the polarization measurement of the other. However, if the two photons were entangled, then the state of one photon would be dependent on the measurement performed on the other photon. This experiment was designed to be appropriate for undergraduate teaching laboratories in quantum mechanics, and may become part of the curriculum at Whitman College.

I also spent two summers exploring aerodynamic limitations of surface coatings on aircraft at Boeing in Seattle, once in the inorganics lab and once in the organics lab. I modeled surface energy processes due to aviation premask used in the aircraft painting process, and helped to develop and implement improvements for the 737 series. I also examined the effects of oxidation on titanium structures in the 787 engines.

I began my graduate studies in August 2014 working with Dr. Jason Jackiewicz as my adviser.


A Possible Mechanism for Driving Oscillations in Hot Giant Planets

E. Dederick & J. Jackiewicz, 2017, The Astrophysical Journal

Exploring Entanglement with the Help of Quantum State Measurement
E. Dederick & M. Beck 2014, American Journal of Physics

The Effects of Internal Stellar Modes on the Evolution of Protoplanetary Star-Disk Systems
Daniel Smith et al. 2014, AAS, 350.08.

Meetings Attended/Will Attend
  • DPS, Oct. 2016
  • JOVIAL Conference, Apr. 2016
  • AAS, Jan. 2015
  • Stanford Helioseismology Workshop, July 2014
  • Murdock College Science Research Conference, Nov. 2013
Teaching and Outreach Activities

I have been a TA for undergraduate astronomy labs at both Whitman College and NMSU. I also participate in elementary school math and science nights, community observing nights, and science lectures to the public.

Updated 8 months ago.