Undergraduate fourth year astrophysics and physics dual degree major at the Illinois Institute of Technology
About
El Morro Castle in San Juan, Puerto Rico
Hello! My name is Leah and I'm a fourth year undergraduate getting my dual degree in astrophysics and physics at the Illinois Institute of Technology. I grew up in a southwest suburb of Chicago called Yorkville, Illinois.
My research interests lie in the formation and evolution of any object in space, and how big events and different properties may effect their evolution. Summer of 2024, I did research through the CIERA REU program at Northwestern University under the guidance of Dr. Tjitske Starkenburg on the dynamics of merging stellar streams. Before that, under the guidance of Dr. Emily Leiner at Illinois Tech, I did modelling of the evolution of a BSS-WD binary star system. You can read more about my work under the Research section.
As the Senior Lead Hawk Ambassador for the Illinois Tech Undergraduate Admissions Office; I give tours, guide prospective students, and help organize the Hawk Ambassador program. My other on-campus job is as a Physics Outreach Ambassador for our Physics Department, where I help with our social media presence and outreach. I'm also on the exec board for the IIT Squirrel Club as President and Founder, as well as the Head of Industry Relations for our Society of Physics Students (SPS). Other clubs I enjoy being involved in include our Tennis Club and Chess Club.
Outside of astrophysics; I love playing instruments, going to concerts (34+), bouldering, travelling, and trying new things! My newest hobby is learning how to hackey sack instead of doom scrolling on social media.
Background Image: A photo I took of the train in Leadville, Colorado!
Research
Unravelling the Dynamics of Stellar Streams in Merging Galaxies
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University
The plot above shows the cartesian coordinates in the xy-plane of stellar streams in an LMC-like galaxy.
The left column shows the initial coniditions (pre-merger) of the streams, while the right column shows the streams
after undergoing a merging event with a Milky Way-like galaxy. The streams are centered around the LMC-like galaxy's center of mass.
The movie above shows a single stellar stream with 1,000 stars represented by each point during a merging event. The left column shows the cartestian coordinates in the xy-plane.
The right column shows the orbital coordinates, to show a representation of what plane the stars are orbiting in.
We see that the merging event causes this stream to split into two separate streams with slightly different orbital planes.
Abstract
Stellar streams are elongated threads of stars in a similar orbit around the outer edges of a galaxy. They form tracers of the galaxy's mass distribution and formation history, and their existence strengthens the argument for galaxies forming hierarchically. There's little known about the formation of these streams because we can only observe ones in our galaxy. However, as we get better telescopes, we will soon be able to see the streams in other galaxies. With these observations, we want to identify which streams formed via a merging event. To do this, we analyze simulations of stellar streams in a low-mass Large Magellanic Cloud(LMC)-like Dark Matter (DM) halo undergoing a merging event with a Milky Way(MW)-like DM halo. This is to get a better understanding of the effects on stellar streams from a merging event to be able to identify them in observations. Identifying these streams will help tell us about a galaxy's formation history and what those stars tell us about the destroyed object. Initially, all of the stars in one stream have the same energy, angular momentum, and orbital plane. After the merging event, we can see how these properties spread out and show the stars getting stripped away from their initial orbit in the dwarf galaxy halo and pulled into the Milky Way-like halo's orbit. We do an in-depth analysis of one stellar stream and would like to look at more going forward to compare and hopefully find a trend that could identify that a stream went through a merging event.
This material is based upon work supported by the National Science Foundation under Grant No. AST2149425,
a Research Experience for Undergraduates (REU) grant awarded to CIERA at Northwestern University. Any opinions, findings,
and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the
views of the National Science Foundation.
References
Johnston, K. V. 2016, in The General Assembly of Galaxy Halos: Structure, Origin and Evolution, ed. A. Bragaglia
Helmi, A. 2020, Annual Review of Astronomy and
Astrophysics, 58, 205
Modeling the Future Evolution of a Blue Straggler Star-White Dwarf Binary System
Illinois Institute of Technology
The orbital periods show that after
stable mass transfer, a wide binary is
formed. On the other hand, unstable mass
transfer leads to orbital decay and formation
of a very close binary with an orbital period
less than one day. The red circles bracket
the range of orbital periods that result from
common envelope evolution
Abstract
Blue straggler stars are stars that appear to be younger and more luminous than expected. These stars are suspected to have been formed from a collision
or mass transfer from a binary companion. WOCS 5379 is a binary star system in the NGC 188 star cluster that consists of a blue straggler star and a Helium
white dwarf star orbiting each other. Using the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) (Jermyn et al. 2023) , we model a
6 Gyr star system consisting of a blue straggler star of mass 1.2 solar masses and a white dwarf with a mass of 0.42 solar masses and a temperature of
15,500K in a 120 day orbit, matching the observed parameters of the real WOCS 5379 system (Gosnell et al. 2019). We model the future evolutionary
trajectories of this binary using two different models: conservative mass transfer, meaning the mass lost by the blue straggler star is fully accreted onto the
white dwarf, and non conservative mass transfer, meaning some percentage of mass lost by the blue straggler is lost from the system and the rest is accreted
onto the white dwarf. Fully conservative mass transfer leads to unstable mass transfer and causes a common envelope to form. Most non-conservative mass
transfer led to the same conclusion, ending with a double white dwarf binary or double white dwarf merger. Highly non-conservative mass transfer in which
90% of the mass is lost from the donor via a wind, and only 10% is accreted to the white dwarf does lead to stable mass transfer, and yields a model that
looks broadly consistent with observed characteristics of symbiotic binaries. These results are interesting because the future evolution of blue straggler-white
dwarf binary systems has not yet been modeled in detail, but they may ultimately form interesting systems such as symbiotics or double white dwarf mergers.
