  We investigate the X-ray and near-infrared emission properties of a sample of
pre-main sequence (PMS) stellar systems in the Orion Nebula Cluster (ONC) that
display evidence for circumstellar disks (``proplyds'') and optical jets in
Hubble Space Telescope (HST) imaging. Approximately 70% of ~140 proplyds were
detected as X-ray sources in the Chandra Orion Ultradeep Program observation of
the ONC, including ~25% of proplyds that do not display central stars in HST
imaging. Many proplyds display near-infrared excesses, suggesting disk
accretion is ongoing onto the central, PMS stars. Among circumstellar disks
that are detected in absorption in HST imaging, we find that X-ray absorbing
column and apparent disk inclination are well correlated, providing insight
into the disk scale heights and metal abundances of UV- and X-ray-irradiated
protoplanetary disks. Jet sources display some of the largest near-infrared
excesses among the X-ray-detected proplyds, suggesting that the origin of the
jets is closely related to ongoing, PMS stellar accretion. Some jet sources
display double-peaked X-ray spectral energy distributions, with soft components
indicative of strong shocks in the jet collimation region. These results
support models in which circumstellar disks collimate and/or launch jets from
young stellar objects and, furthermore, demonstrate that star-disk-jet
interactions may contribute to PMS X-ray emission.
