Debris disks present a wide range of sizes and structural features (inner cavities, warps, offsets, rings, clumps) and there is growing evidence that, in some cases, they might be the result of the dynamical perturbations of a massive planet. They are evidence that these stars harbor a reservoir of dust-producing plantesimals on spatial scales that are similar to those found for the small-body population of our solar system. Modeling and Observations of Debris Disksĭebris disks are disks of dust observed around mature main sequence stars (generally A to K2 type). By using a model that fits for photometric and mid-IR datasimultaneously, we gain a deeper understanding of the structure and composition of the debris disk systems. Our goal is to compare this data to the model. We have spatially-resolved optical and near-IR images of the disks from HST. The Spitzer data includes mid-IR spectroscopy and photometry. We have data on nine targets from Spitzer and Hubble Space Telescope. ![]() We apply Mie theory to calculate the dust absorption and emission within debris disks. In order to characterize the properties of the circumstellar dust, we create models of debris disks in order to find the composition. Zimmerman, Mara Jang-Condell, Hannah Schneider, Glenn Chen, Christine Stark, Chrisĭebris disks play a key role in exoplanet research planetary formation and composition can be inferred from the nature of the circumstellar disk. We will also divide our observations into two visits, to search for signs of star-grazing exocomets, which are seen in both Beta Pic and 49 Cet.Ĭreating Compositionally-Driven Debris Disk Dust Models We will measure column densities of the most important gas species, find the relative elemental gas abundances, and determine the gas mass using a powerful gas disk modeling code. This disk is edge-on and contains circumstellar atomic gas (CII). We propose extending our intriguing studies of debris gas with STIS UV spectroscopy of a highly promising debris disk system, Eta Tel. The UV bandpass is particularly important, since strong transitions of numerous atomic and molecular species lie there. This technique is far more sensitive to small amounts of gas than emission line studies. What are the typical gas-to-dust ratios in debris disks? What is the chemical composition of debris gas and its parent material? The answers to these questions have profound implications for terrestrial planet assembly and the origins of planetary atmospheres.Most detections of debris gas to date were achieved with line of sight UV/optical absorption spectroscopy of edge-on disks, using the central star as the background source. Only two debris disks have measurements of their gas composition, which is shockingly carbon-rich (Beta Pictoris and 49 Ceti). More information can be provided by their gas content, but astonishingly little is known about it. Their dust component has been extensively studied, yet has provided little information about disk chemical composition. Inventoring Gas in Debris Disks: UV Spectroscopy of Eta Telĭebris disks stand between gas-rich protoplanetary disks and mature planetary systems, shedding light on the late stages of planet formation. Finally, I will touch on upcoming studies of gas in protoplanetary and debris disks, some at UV wavelengths, some at far-IR and sub-mm wavelengths. New insights obtained from UV spectroscopy will be highlighted, as well as some new puzzles. In this talk, I will outline our picture of the evolution of protoplanetary disks and discuss the importance of the gas component. UV spectroscopy has made some unique contributions by probing the elusive but vital gas component in protoplanetary and debris disks. Many are familiar with the extensive work on the cold circumstellar dust present in these disks done using infrared and sub-millimeter photometry and spectroscopy. Over the last two decades, observations of protoplanetary and debris disks have played an important role in the new field of extrasolar planetary studies. ![]() Gas in Protoplanetary and Debris Disks: Insights from UV Spectroscopy
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