The Kinematics of Massive Stars and Circumstellar Material in the Carina Nebula

Abstract

This dissertation presents the results of three related projects, each focusing on an aspect of the massive stars in the Carina Nebula and how they impact their surroundings. First, I use the proper motions of dense gas ejected by η Carinae to show that this luminous blue variable (LBV) has experienced major eruptions not just once but three times in the past millennium. The three eruptions show distinctly different symmetries: the thirteenth-century event was essentially one-sided, while the sixteenth-century event and the nineteenth-century Great Eruption were bipolar but not aligned with each other. These observations provide new constraints to theoretical models of η Car and LBVs. In the second project, I constrain the proper motions of five other massive stars in the Carina Nebula. Each of these five has a stellar wind bow shock, but I find that none are runaway stars. In two cases, the bow shocks, which face a cluster that is driving large-scale flows of ionized gas, point at right angles to the motion of their stars. In the other three cases, both feedback-driven gas flows and stellar motion may be factors in setting bow shock orientation. The third section of this dissertation is a survey of the radial velocities of the Carina Nebula’s full O-star population, combining new spectroscopy with a thorough review of values from the literature. The radial velocity distribution supports a common distance to the region’s various clusters and subclusters. Comparison to molecular gas velocities shows that feedback from the Trumpler 16 cluster (home to η Car), has accelerated a dense cloud toward us and possibly triggered additional massive-star formation. Comparison to ionized gas velocities shows that the feedback-driven expansion of the H II region is not spherical and is likely constrained by an unseen dense cloud on the far side.