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Exoplanet Formation . . .
I am working on the theory of planetary formation
in the context of low-mass (late-type) M-dwarf stars.
Exoplanets have been discovered in so many places that
we never would have expected 10 years ago, that now we
really need to explore the possibilities if we want to
be able to lead discovery rather than chasing after.
I am particularly interested in trying to
develop a comprehensive framework within which we
can understand and predict the characteristics of
Earth-like planets. This is becoming possible as the
understanding of the formation and movement of the
gas-giant planets becomes clear.
Paper:
Formation and Detection of Terrestrial
Mass Planets around Low Mass Stars,
Submitted to Icarus (2008)
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. . . and Detection
Which is all very interesting, but now
the point that makes it science and not just conjecture:
can you prove (or disprove) it?
This helps makes sense of why I'm focusing on low-mass
M-dwarf stars. Since these stars are so nearby and
physically small, we have the potential to detect the
photometric dip caused by these terrestrial planets
in transit in front of their host stars. The only
concern is the high levels of photometric variability
exhibited by this class of stars.
I've modified a Monte-Carlo code which was
originally set up to simulate a transit-search campaign
comprised of amateur astronomers looking for gas-giants.
Now it allows simulation of arbitrary observations of any
target list and planetary population. This allows me
to get realistic predictions for the utility of various
methods of searching for transits without having to go
out and build anything.
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Galaxy Collisions
As part of my `2nd Year Project',
I began work with Greg Laughlin
on determining the specifics (orbital
parameters) of a galaxy collision given an image of the
collision in progress. I used a Genetic Algorithm to
intelligently search through the parameter space of
possible collisions and compare the results to how
it appears on the sky.
Kirsten Howley has done an
excellent job in carrying this work forward in the
context of understanding the interaction between
Andromeda (M31) and one of it's satellite galaxies
(NGC 205). Incorporating many more constraints on
the system than simply the visual appearance.
Paper:
Darwin Tames an Andromeda Dwarf:
Unraveling the Orbit of NGC 205
Using a Genetic Algorithm,
Accepted to The Astrophysical Journal (2008)
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Ionization in the Early Universe
I worked with
Mike Kuhlen and
Piero Madau
on simulations of reionization in the early universe.
We looked at the visibility of Hydrogen gas as the
universe expands and cools and how collisional heating
in dense environments and the first luminous sources
(mini-Quasars) affected the 21cm radiation brightness.
Paper:
The Spin Temperature and 21cm Brightness of the
Intergalactic Medium in the Pre-Reionization Era,
The Astrophysical Journal (2006)
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Dark Energy
As an undergraduate I worked for
Kim Griest
exploring the effects of quintessence models
on universal expansion. I calculated the universal
acceleration rate, up to the present epoch, from
a succession of scalar inflationary fields.
The idea was to explain the variable expansion
of the universe with the overlapping rise and
fall of the various fields.
Primarily, I rolled up my sleeves
and got into research a bit. I got a taste of
what it's like to work on a problem that no one
knows the answer to... yet.
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