I study the gas dynamics in star forming regions, including both the molecular and ionized gas populations. Though observing these gas components, I can directly test predictions from theories of star formation. I study the gas dynamics at high resolution using state of the art radio interferometers such as ALMA, CARMA and the newly expanded VLA (or JVLA/EVLA).

High Mass Star Formation

My primary research focus is on studying the formation of the most massive stars in our Galaxy. These beasts shape the Galactic ecosystem and are responsible for forming all of the heavy elements; from the Iron in our blood to the metals in a Euro coin. How these massive stars live and die is well constrained, how they form, is not. The fundamental question here is, how can stars upwards of 100 solar masses form, when current theories can't seem to get much further than 30 solar masses? My recent studies, the first to draw comparisons between the ionized and molecular gas dynamics, suggest that accretion may be able to continue in the presence of an HII region (an ionized gas bubble produced by the forming star) for some of the most massive stars currently forming in our Galaxy. In Klaassen et al. (2013b), I showed that the gas dynamics in the high-mass star-forming region K3-50A (at 10^6 solar luminosities, one of the most massive star forming regions in our Galaxy) are consistent with the theoretical predictions from ionization driven outflows (Peters, Klaassen et al. 2012).

I am currently leading a study to followup on these findings in four high-mass star-forming regions with new VLA observations of the ionized and molecular gas populations.

Low Mass Star Formation: Studies using ALMA Science Verification data

Massive stars form less frequently than those closer to the mass of the Sun. Understanding the general mechanism responsible for forming most stars and planets therefore requires studying nearby lower-mass star-forming regions.

ALMA, still in its early science phase, is already proving transformational in the study of low-mass star-formation. In the early days of star formation studies, disk winds were predicted as a mechanism for dispersing the build-up of angular momentum in the accretion disk (i.e. Pudritz and Norman, 1983). It wasn't until ALMA imaged the disk of HD 163296 that the first disk wind was imaged (Klaassen et al. 2013a), showing that these types of winds are real.

From the same observatoins, we were also able to show the location of the CO snow line in the same disk (Mathews, Klaassen et al. 2013). This study, along with Qi et al. (2013, for TW hydra) showed the first images of snowlines outside our own solar system. In the hunt for planets, and finding the right conditions for forming different types of planets, snowlines are important modelling tools for finding what types of matieral are available to be incorporated into those planets.