Grad Student Spotlights
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Kassandra is a second-year graduate student working with Professor Dong Lai on the dynamics of exoplanetary systems, with a focus on the orbital evolution and migration of hot Jupiters. Currently, she studies the dynamics of "high eccentricity migration," in which planets can be perturbed by distant companion stars, and be periodically excited into very eccentric orbits. Due to dissipative tidal forces between the planet and host star, the planetary orbit shrinks, causing the planet to gradually migrate inward and settle into a tight orbit around its host star.
Motivated by observed spin-orbit misalignments in hot Jupiter systems, Kassandra's work focuses on the spin-orbit dynamics between the migrating planet and the host star. When the migrating planet is at high-eccentricity, the host star experiences torques from the planet, causing the stellar spin axis to evolve in a complex manner. In collaboration with Professor Lai and Physics graduate student Natalia Storch, she is seeking observational consequences of these spin dynamics. By simulating the evolution of the stellar spin, she is comparing the theoretical results with the distribution of observed spin-orbit misalignment angles. Such calculations are useful for distinguishing between various possible migration channels for hot Jupiters.
Kassandra's research interests include the general area of stellar and planetary astrophysics, circumstellar disks, and dynamics. Using a combination of numerical simulations and semi-analytic techniques, her long-term goal is to better understand the diverse architectures of observed exoplanetary systems. In addition to research, she is also taking classes, and participating in Cornell's Ask an Astronomer outreach program. Outside of astronomy, she has a variety of activities and hobbies, including sewing and knitting, dance, and hiking around Ithaca.
Kassandra chose to come to Cornell because of the research opportunities in the department and the strong sense of community among its members. "The environment here is very friendly, yet also stimulating. As graduate students, we have opportunities to interact and collaborate not only with the local faculty and research scientists, but also with visiting scientists, and weekly colloquium and seminar speakers. These interactions are really helpful."
Kassandra proposed for and was awarded an NSF Graduate Research Fellowship to support her in her PhD.
My research focuses on studying and understanding the hydrologic cycle of Titan, a moon of Saturn, and the only other known body in our solar system with an active hydrologic cycle. To this end, my research. working with Alex Hayes, focuses on studying the frequency, duration, location, and characteristics of storms on Titan. We do this through a combination of ground and space based observations (using the Cassini spacecraft currently in orbit around Saturn) to image Titan in the near-IR, where we can see through Titan's thick atmosphere.
Titan's atmosphere (and surface) remain an extremely complex environment, with new mysteries being solved and uncovered each day. The observing campaign we have been conducting to monitor cloud activity hopes to provide only a small piece of the puzzle to understand this complex system, similar to that of Earth's, which can perhaps even provide insight into our own atmosphere.
In addition to this modelling effort, I am also interested and involved in a set of instrumentation projections working in the visible, near-IR, and sub-millimeter/millimeter wavelengths. My current instrumentation project involved working with Michael Niemack on designing and building a Fourier Transform Spectrometer (FTS), designed to work in the submillimeter/millimeter to be used for testing the transmissive properties of various optical components currently being designed for telescopes operating in this wavelength regime.
Outside of research, Paul is currently a TA for introductory astronomy courses, teaching students about everything from how the universe began to how it will end. He also is an avid baker and “loves all things food."
Matt Hankins is a second year PhD student working with Professor Terry Herter on the Faint Object InfraRed CAmera (FORCAST) instrument for the SOFIA Telescope. SOFIA is a modified Boeing 747SP that housess a 3m infrared telescope. Matt participated in the delivery of the FORCAST instrument to NASA. He described it as an ‘incredible experience,’ and that ‘going on observing runs onboard SOFIA is really a unique experience.’ He looks forward to going back out on observing runs in the coming year.
He is interested in massive evolved stars and young stars as well as the galactic center which is home to many of these kinds of objects. Matt currently works on studying infrared emission in the center of our galaxy (the inner ~100 light years near the supermassive black hole Sgr A*). The central part of our galaxy has many interesting properties that are different from other parts of the galaxy. Matt is currently studying a set of evolved dusty Wolf-Rayet (WR) stars. The stars are interesting because they are extremely luminous in the infrared (IR) compared with other WR stars. Matt’s work focuses on understanding the dust formation mechanism and the mass loss of the stars to understand evolutionary state of the stars. In addition to this work, Matt is also studying a nearby HII region. By studying the IR emission in this region it is possible look for evidence of embedded protostars which may be contributing to the heating of the dust in the region.
Outside of academics, Matt enjoys hanging out with other grad students and participating in the Astronomy Grads Network (AGN) (http://grads.astro.cornell.edu/index.html) activities. Matt participates in outreach activities like Ask an Astronomer, Museum in the Dark, and Focus for Teens. Matt is also a bit of a movie buff and also enjoys music, sports, and trivia nights at the Big Red Barn.
When applying for graduate programs, Matt was drawn to Cornell because of the research opportunities offered as well as the welcoming environment in the department. “I’ve really enjoyed my time here at Cornell. Initially, I was really interested in the numerous research opportunities available within the department. Also, I found that people in the department are generally friendly and very approachable.”
T.K. Daisy Leung
I am a third year graduate student working with Professor Dominik Riechers on studying the interstellar medium (ISM) properties of distant galaxies. Despite great progress made in studies of galaxy formation and evolution over the past decade, we are only beginning to fully understand how galaxies interact and evolve, and which key mechanisms are responsible for driving the bulk of stellar mass assembly in the universe. Since the ISM is the natal environment from which stars are formed, tracing the molecular cold gas in the ISM — the immediate fuel for star formation — via e.g., carbon monoxide (CO) molecules is particularly important. By characterizing the ISM of these distant galaxies, my research aims to improve our current understanding of how galaxies and their supermassive black holes were formed in the early universe and how they have evolved since then. Most of my research is done by observing the light that was emitted billion years ago using arrays of telescopes (interferometers) that operate at radio and sub-millimeter wavelengths. For instance, some of my work (e.g. Leung & Riechers 2016) has made use of the data collected from the Submillimeter Array, which is shown in the background of this photo.
Thinking that my work has an impact on the quest of uncovering the mysteries of the universe — a common goal to all human beings — is the impetus to my work. Beyond my research contributions to the field, I also value my work as a teaching assistant, an important role that allows me to share my fascination towards the subject of astronomy with undergraduate students. It is my humble wish that I too can spark interests in our students at Cornell who may one day become future scientists.
As someone brought up in the tropics, I do not enjoy dealing with the brutal winters here in Ithaca, but as I reflect on the past two years here, I have never regretted my decision of coming to Cornell to pursue my doctoral degree, thanks to the group of supportive colleagues and my advisor who have provided me with an excellent learning environment. Besides work, I enjoy exploring outdoor sceneries, hiking and doing landscape photography. I have been taking timelapse videos around Ithaca that I anticipate to release when I graduate.
Research Area: Galaxy Formation and Evolution, High-redshift galaxies, Inter-stellar Medium in Galaxies
Research Interests: I am a fifth-year graduate student working with Professor Dominik Riechers on measuring gas and dust properties of galaxies at high-redshift.
Most of my work involves analyzing the Very Large Array CO Deep Field (CO luminosity density at high-z; COLDz), a large VLA project to measure the cold molecular gas content of galaxies at redshift 2 to 3, the peak epoch of cosmic star formation. The molecular component of the inter-stellar medium is the fuel for star-formation in galaxies, so investigating the amount of available gas, and its physical state, in galaxies at this crucial epoch of galaxy formation is necessary in order to clarify what drove the formation of the bulk of the stars that we see in galaxies today. I search the data for CO line emission and analyze the candidate galaxies.
I am also heavily involved in projects that exploit the power of ALMA (the latest Millimeter/submillimeter interferometer in Chile) to study dust and gas emission (e.g. through Far-IR fine structure) in “normal” galaxies in the first billion years of cosmic time (z>5). While it is clear from the preliminary results that the dust emission properties of these galaxies are different from nearby galaxies, our investigation attempts to establish the physical context for the conditions of the gas (e.g. ionized vs. neutral fraction, radiation field properties) in “typical” galaxies at redshifts higher than previously observed.
When I am not analyzing data I love going for bike rides in the Ithaca area, hiking in the mountains, cooking (Italian and other) or going to the Farmers Market.