Marina Kounkel

Vanderbilt University, Postdoctoral Scholar





My name is Marina Kounkel, I am a postdoctroal scholar in the Physics and Astronomy Department at the Vanderbilt University , working closely with Keivan Stassun. Much of my research involves observing dynamics of the young stars.

Most stars form in clusters. Currently the exact method in which the stars move within in the clusters is understood in a broad sense. However, due to large uncertainties in the proper motions we are frequently restricted only to the motions in one dimention (radial velocity). This makes it difficult to analyze the detaild motions of the individual young stars which may not always belong to a normal distribution. Recent advancements in the precision astrometry by such observatories as Very Large Baseline Array and Gaia Space Telescope have begun to allowed us to take a closer look into the kinematic structure within the young stellar clusters.

Approximately half of all stars form in a binary star system, and the multiplicity fraction is set early on in the life of the young stars in a cluster as it is highly improbable for two stars to come together by a complete accident later in their lives. Nonetheless, the factors which cause a formation of a binary or a higher order multiple system are presently not well understood, as they depend on a multitude of properties, not the least of which are the mass of the primary star and the environment in which a star is formed. In general, a motion of any two stars around each other is very regular, and through a fit of their orbit it is possible to understand many properties of these stars. However, this motion does become increasingly more complex and unstable if either a third star of a multiple system or the collection of nearby stars within a cluster are added to the mix. This could create a scenario in which a young star is ejected from a cluster, and these "orphans" may be apparent through comparing their kinematical signatures to those of the cluster itself, this could lead to an improved understanding how do young stars interact with each other within a cluster.

Motions of the stars in the sky that we precieve from the Earth can be attributed to many factors not the least of which involves the change in perspective of the nearby stars due to the motion of the Earth around the Sun. Through analyzing these minute shifts it is possible to measure distance towards these stars. Without knowing the distance it is very difficult to determine the total ammount of light a star emits, and, in the cases of young stars in particular, this causes a challenge in the mass or age determination as well. With accurately determined distances we could not only better understand the emission processes of the young stars, but also we could analyze a 3-dimentional structure of the young clusters as well.


Marina.Kounkel (at)

Department of Physics and Astronomy
6301 Stevenson Center
Nashville, TN 37240