HD 100546 - A Herbig Star Surrounded by a Formative Planetary System

A protoplanetary system consisting of at least two giant planets surrounds theyoung nearby Herbig Be star HD 100546. The inner protoplanet orbits within 13 AUof the star and is exposed to strong stellar UV and Xray radiation. Thedetection of very warm disk gas provides evidence that stellar heating isaffecting physical conditions in the planetforming environment. Chandradetected HD 100546 in two short 2.6 ks exposures but there are insufficientcounts to reliably extract spectral parameters. We propose a deeper followupobservation with XMM to obtain a spectrum of sufficient quality to determine theXray absorption, temperature distribution, and luminosity. We will use the XMMdata to determine the Xray heating and ionization rates in the disk. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]