About Me
Education: Ph.D. Astronomy, Cornell University (2024); M.S. Astronomy, Cornell University (2020);
B.S. Astrophysics, University of California, Los Angeles (2018)
Research Interests:
Theoretical astrophysics, including astrophysical dynamics,
stellar and planetary astrophysics, compact objects, Milky Way Galactic Center.
Observational exoplanet science, especially for systems around evolved stars and white dwarfs.
Nonlinear dynamics and chaos, with applications to astrophysical systems.
Publications: ADS
Research
Planet engulfment events.
Sun-like stars (~1-2 solar mass) will become red giant stars near the end of their lives, swelling more than 100 times in size.
During this stage, planets orbiting close to their host stars are likely to be engulfed and destroyed.
Depending on the size of the planet, the process of engulfment can have major consequences for the host star's structure and later evolution,
and it can produce transient phenomena that we can observe from Earth.
The greatest effects occur when a Jupiter-sized gas giant planet is engulfed while the red giant star is close to its maximum physical size.
My collaborators and I have studied the consequences of planet engulfment for red giant stars using the stellar evolution code
Modules for Experiments in Stellar Astrophysics (MESA).
We found that red giant stars can become significantly brighter over several years after engulfing a gas giant planet;
this suggests that wide-field sky surveys, like ZTF and Rubin/LSST, can detect planet engulfment events in action
(maybe like this one!).
We also found that the most massive planets (5-10x the mass of Jupiter) can cause their stars to produce a bright eruption
called a luminous red nova.
Our paper on this work has been accepted to ApJ. You can read a preprint here.
If you are interested in studying planet engulfment events in MESA, you can download our source code here.
Dynamical origins of white-dwarf pollution.
More than 1/3 of white-dwarf stars are constantly ingesting debris from tidally disrupted planetary bodies previously
in orbit around these stellar remnants. This "pollution" offers a unique window into the final stage in the life cycle
of a planetary system, particularly from the perspective of long-term dynamical evolution. I am interested in
applying dynamical theory to understand the processes by which planetary debris is delivered to a white dwarf.
White dwarf pollution from "secular chaos" in remnant planetary systems: ADS link
Why don't we observe white-dwarf pollution from exocomets? (submitted, preprint coming soon)
Tidal interactions and high-e migration in planetary and stellar systems.
Many forms of dynamical evolution in astrophysical systems lead to close encounters between a planet and
a star or between two stars. At these close distances, tidal forces between the objects lead to a variety of
interesting phenomena, ranging from the excitation of a body's internal oscillations -- in essence, making it
ring like a bell -- to tearing it apart entirely. Nature seems to produce all of these outcomes in different settings.
I have studied high-eccentricity migration in a few different papers so far, mostly in relation to surviving planetary
systems around white dwarfs.
High-e migration of a Jupiter-sized planet in orbit of a white dwarf: ADS link
Migration of asteroids around white dwarfs: ADS link
Service & Teaching
Coming soon...
Contact
Email: coconnor [at] astro [dot] cornell [dot] edu
Address: Space Sciences Building, Cornell Univ., Ithaca, NY 14853