The Kinematics of Massive Stars and Circumstellar Material in the Carina Nebula
AuthorKiminki, Megan Michelle
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PublisherThe University of Arizona.
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AbstractThis 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.
Degree ProgramGraduate College