About me
My name is Marina Kounkel, I am an assistant professor in the Physics and Astronomy Department at the University of North Florida. Much of my research involves observing dynamics of the young stars. Star formation is a clumpy process, and this clustering happens across all scale, from the size of individual stellar systems, to the subtructure within star forming regions, to the distribution of these star forming regions across the Galaxy. The history of how these structures has formed, and how it is going to evolve over time, as well as the fundamental properties of these structures are imprinted in the stellar kinematics.
Measuring these kinematics is only possible thanks to several large astronomical surveys. Gaia space telescope is meticulously measuring accurate positions of stars, from which it is possible to derive distances and motions in the plane of the sky for over 1.6 billion stars across the entire sky, singlehandedly revolutionizing Galactic astronomy overnight with the first major release of these data. Radial velocities - the last remaining component of motion - is accessable through high resolution spectroscopic surveys, such as SDSS-V APOGEE. Combining these parameters together, it is possible to identify kinematically coherent groups of stars that have most likely formed together from the same molecular cloud at the same time. In populations that are young enough, it is still possible to reconstruct the initial conditions that have influenced the formation of these stars, such as supernovae, cloud-cloud collisions, gravitational feedback, and many others. Through careful analysis of stellar ages, we can see how and when different events were triggered, and how they propagate throughout a population. And, as our ability to measure ages of increasingly larger number of stars improves, we can reconstruct the history of our Galaxy.
For this, it is crucial to better understand stellar properties, including but not limited to their masses, their radii, their temperature, their rotation rate, their magnetic activity, as the combination of these parameters allows us to better probe stellar ages. These measurements are non-trivial to perform, and unfortunately they often depend on comparisons to theoretical models of stellar evolution, which may not always be sufficiently precise. Because of this, it is also necessary to carefully isolate the sample of stars for which it is possible to perform all of these measurements, as it will help improving the calibration for all the other stars as well.
