Hello! My name is Samantha Wu and I am a final-year Ph.D. Candidate in Astrophysics at Caltech. For my research, I work on
theoretical stellar astrophysics, using numerical calculations to study the interiors of stars. My Ph.D. advisor is Jim Fuller.
Before coming to Caltech, I earned bachelor's degrees in Applied Mathematics and Astrophysics at UC Berkeley.
At Berkeley, I worked on TDEs with Dr. Eric Coughlin and the numerics of GRMHD simulations with Dr. Philipp Moesta.
Between graduating from Berkeley and starting at Caltech, I worked with Dr. Enrico Ramirez-Ruiz at UC Santa Cruz on multi-dimensional
hydrodynamical simulations of stellar mergers.
Publications: on ADS
Research Interests: My current focus lies in the realm of stellar evolution and internal stellar oscillations
with applications to pre-supernova outbursts and tidal evolution of exoplanets. I have also worked on interacting stellar
binaries and tidal disruption events.
A substantial fraction of observed core-collapse supernovae across all spectroscopic types have exhibited
signatures of interaction with circumstellar material (CSM) produced by a pre-supernova outburst of material. In some events, luminous pre-supernova
outbursts have also been detected.
To address this observational puzzle, I have modeled the excitation and transmission of internal gravity waves excited in the cores
of massive stars, which can couple with acoustic waves in the envelopes of these massive stars and deposit their energy. This energy
deposition has the potential to unbind mass and produce luminous outbursts in the weeks to years before core-collapse. I
that certain progenitor mass ranges are more likely to exhibit outbursts than others, and wave energy transport can precipitate
of stripped helium stars.
Pre-supernova mass loss may also be triggered by binary mass transfer between a massive star and its companion. I
for low-mass helium star progenitors that mass loss during late-stage nuclear burning is consistent
with inferred CSM properties of a subset of type Ibn supernovae and ultra-stripped supernovae.
Tidal dissipation in star-planet systems
Dr. Janosz Dewberry ,
I am studying the dynamical tidal response of stars, which consists of normal modes of stellar oscillation
that are excited by the tidal potential of a planetary companion. My current research involves modeling
normal modes of oscillation in realistic stellar profiles of fully convective or partially convective stars in order to
calculate the frequency-dependent tidal dissipation of the star, coupled with the stellar evolution from the pre-main sequence
throughout the main sequence. With this approach, I have resolved orbital migration due to resonance locking, a mechanism by
which the tidal potential of the planet resonantly excites a stellar oscillation mode over a prolonged period of time,
leading to enhanced tidal dissipation and rapid orbital migration.