First Science with CHARA Fringe Tracker: Imaging Planet-forming Disks around Young Stars

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Dr. Monnier will build on recent advances in interferometry to develop an important new tool for studying young stellar objects: "model-independent" imaging with milli-arcsecond angular resolution. The project will be carried out using the newly commissioned Michigan Infra-Red Combiner, which links all six telescopes of the Georgia State University's Center for High Angular Resolution Astronomy (CHARA) optical interferometer at Mt. Wilson in California. CHARA's imaging capabilities will be extended even further using a new fringe tracker also developed by Dr. Monnier. This will be used to "phase up" the array at one wavelength while observing in another - a kind of adaptive optics for interferometry.The scientific focus of this project is to exploit the new order-of-magnitude improvement of sensitivity for imaging the inner disks of young stellar objects in the process of planet formation. Initial observations of young stars using a two-telescope combiner at CHARA have already revealed surprisingly strong emission from inside the dust destruction radius, tentatively associated with hot gas. Other evidence is also accumulating that the inner regions of accretion disks are quite dynamic and time-variable, and imaging will provide a uniquely powerful tool for discovering the source of these changes. This research promises to uncover connections between jet eruptions and disk instabilities, likely critical for understanding planet formation and subsequent migration. Because orbital time scales are less than about a year in the inner disk, the multi-epoch studies to be carried out should reveal the orbital motion of any clumps or inhomogeneities.Imaging is a general-purpose capability that is lacking in visible and infrared interferometry, and is only now possible with current facilities and new beam combination techniques. The software and data analysis tools developed in this project will be available to the whole community and can be applied to diverse areas of stellar astronomy beyond this project.The advances in infrared interferometry have been made possible through the improvement in infrared detectors. As experimentalists and IR camera builders, Dr. Monnier and his team will share these exciting developments with the greater public through an innovative portable exhibit concept based around today's new thermal infrared cameras. Partnering with the Ann Arbor Hands-On Museum, a portable visible-infrared stereo camera system, deployable in a variety of teaching environments, will be developed. This engaging learning tool will allow students of all ages to explore their Universe with "new eyes."