ASTR 331 is an upper-level astrophysics course covering the physics of stars and stellar evolution, including stellar atmospheres and the connection to astronomical observables, stellar interiors and nuclear fusion, formation and evolution of stars of different masses.
Prerequisites: ASTR 261, or both ASTR 161 and ASTR 181, PHYS 242 or PHYS 252 (may be taken concurrently). PHYS 243 is recommended.
ASTR 161 is an introductory astronomy course with a focus on the sky and the Solar System. In this course students learn about: how observations of the sky are made and interpreted, the diversity of bodies in the Solar System, how they formed, and how they compare to other planetary system.
A working knowledge of algebra and geometry is expected, and a scientific calculator (with scientific/exponential notation and trigonometric functions) will be required.
Core: biological and physical sciences.
Simeon began working with me in the summer of 2024. His project was to examine the change in the core-mass fraction of planets as a result of giant impact events, and how this varies with the initial mass and core-mass fraction of the bodies, and the speed of the impact. For this he used the Smoothed-Particle Hydrodynamics (SPH) code SWIFT.
Gray worked with me for 18 months beginning in Fall of 2023. The main part of his project was to use the iSALE shock physics code to simulate a set of ice-impact experiments that I had previously performed in Madrid. In particular, we were interested in understanding how the water pockets present in some of the experimental ice blocks affected the craters produced. Once that part of the project was completed, he then began conducting simulations of impacts into water pockets in the ice shell of Jupiter's moon Europa.
Loic worked with me over the summer of 2018 through the undergraduate fellowship programme run by the Centre for Planetary sciences at the University of Toronto. His project involved running traditional perfect-merging N-body simulations of terrestrial planet formation and examining the results. The end goal of the was to construct a model to compare the outcomes of the perfect merging simulations with what we might expect given our knowledge of the true, non-perfect outcomes of giant impacts between planetary embryos, as described by work such as Leinhardt & Stewart 2012.
Outside a formal advisory role I was also fortunate during my first stint at Arizona State University from 2014-2016 to meet and work closely with two graduate students, Viranga Perera and Travis Gabriel.
Viranga is now teaching faculty at the University of Texas, Austin, while Travis works for the USGS. You can find more about the projects we worked on together on the projects and publications pages and I encourage you to visit their own websites to learn more about their work!
Terrestrial planet formation is a very active field, and the formation of Earth and other planets has undergone a revolution in terms of solar system theories and extrasolar planetary exploration. In this course students learnt how we think the planets formed as dynamical, physical, and thermodynamical systems, with an emphasis on the physical process of accretion and its clues in geochemistry, planetary structure and orbital architecture. The course was quantitative and included regular problem sets and reading assignments, culminating in a short research paper or literature review and a final written exam.
My role as a supervisor was to go through the solutions to the weekly problem sets with the students in groups of 2-3.
Fluids are ubiquitous in the Universe on all scales. As well as obvious fluids (e.g. the gas that is in stars or clouds in the interstellar medium) a variety of other systems are amenable to a fluid dynamical description - including the dust that makes up the rings of Saturn and even the orbits of stars in the galactic potential. Although some of the techniques of conventional (terrestrial) fluid dynamics are relevant to astrophysical fluids, there are some important differences: astronomical objects are often self-gravitating or else may be accelerated by powerful gravitational fields to highly supersonic velocities. In the latter case, the flows are highly compressible and strong shock fronts are often observed (for example, the spiral shocks that are so prominent in the gas of galaxies like the Milky Way).
In this course, we consider a wide range of topical issues in astronomy, such as the propagation of supernova shock waves through the interstellar medium, the internal structure of stars and the variety of instabilities that affect interstellar/intergalactic gas. These include, perhaps most importantly, the Jeans instability whose action is responsible for the formation of every star and galaxy in the Universe. We also deal with exotic astronomical environments, such as the orbiting discs of gas which feed black holes.
Image credit: Alan Jackson, Merton College, Oxford - rear of Fellows quad