Research

Research Interests

My research primarily focuses on the physics and evolution of massive star systems, however, my interests extend to all types of stellar and/or binary systems. Throughout my career, I have worked with ground- and space-based photometric and spectroscopic data and I have worked with systems all across the HR Diagram. Currently, my primary line of reasearch focuses on non-spherical massive stars. I am particularly interested in how the 3D geometry of these systems can change not only their evolution, but also our interpretations of the physical parameters of these systems.

non-spherical massive stars

Throughout the life of a massive star, deviations from spherical symetry are common, whether due to rotation or binary interactions. These deviations from spherical symetry can have a large impact on the evolution of the star as additional internal mixing processes become relevant in these configurations. During my PhD I worked on massive overcontact binaries to try to better understand how the extreme geometry during this phase affects the future evolution of these systems. We found that not only do the internal mixing processes behave differently than what we had expected, but also that the analysis techniques that we typically use to study these non-spherical systems can lead to biases in our interpretation of the surface parameters (see our 2019, 2020, 2021, and 2022 papers). Recently, in my 2023 Letter, I characterized these effects for rapidly rotating systems and showed that using 1D atmosphere models can bias both the temperature and the measured elemental abundances if the 3D geometry is not properly accounted for.

stellar mass black holes and bloated stripped stars

An important phase in the evolution of massive binary systems involves the formation of stellar mass black holes with a main sequence or evolved stellar companion. The detection and confirmation of these types of systems has proven to be a difficult task with many important caveats to consider. For example in our 2020 paper published in Nature, we discuss how stellar sources can mimic black hole signals especially if the detection is based on certain spectral lines. Many of these initial black hole detections have since been proven to be less exotic (but equally interesting) bloated stripped star companions by our group (see for example Shenar et al. 2020, Bodensteiner et al. 2020, and Frost et al. 2022 ). Although, a few detections still remain promising ( Shenar et al. 2022, and Mahy et al. 2022 )

binarity and binary statistics

While studying individual systems can give valuable insights into specific evolutionary phases, looking at the bulk statistics of a sample can allow us to understand how common or uncommon specific orbital configurations are. I have been part of a few different collaborations studying this from both a photometric and a spectroscopic point of view. On the photometric side, we looked at the binary properties for systems in both the Kepler and TESS fields of view (see Abdul-Masih et al. 2016, Kirk et al. 2016, and Prša et al. 2022 ). On the spectroscopic side, we looked at the atmospheric parameters for a group of massive stars in the Tarantula region of the LMC ( Mahy et al. 2020).