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Session 49 - Young Stellar Objects.
Display session, Tuesday, January 14
Metropolitan Ballroom,

[49.06] A Search for Thermal Infrared Emission from Three Silhouette Disks in Orion

T. L. Hayward (Cornell U.), M. J. McCaughrean (MPIfA)

We have searched for mid-infrared emission from the Orion Nebula silhouette circumstellar disks 218-354, 183-405, 121-1925, and 167-231. We report a positive detection of 218-354, possible detections of 121-1925 and 167-231, and no detection for 183-405. Our fluxes for 218-354 confirm the near-infrared excess detected by McCaughrean amp; O'Dell (1996), and the optical to mid-infrared spectral energy distribution is similar to that of T Tauri stars with moderately luminous disks. A reddened stellar continuum plus a standard circumstellar disk model with a dust luminosity of 2 L_ødot fit the available data fairly well and implies that we are only detecting emission from the innermost regions of the large disk seen in silhouette. Our upper limit for 183-405 shows that the mid-infrared luminosity of its disk is very weak relative to its central star. In addition to the silhouette disk sources, our target fields also contain several other sources, four of which we detect in the mid-infrared. All of these sources show infrared excesses typical of circumstellar disks, supporting the suggestion that such disks are common in the Trapezium Cluster.

Program listing for Tuesday