  Here we analyze the first simultaneous X-ray, ultraviolet, optical, infrared,
and centimeter observations of a T Tauri star (TTS). We present three epochs of
simultaneous Spitzer and VLA data of GM Aur separated by ~1 wk. These data are
compared to previously published HST and Chandra observations from which mass
accretion rates ($\dot M$) and X-ray luminosities, respectively, were measured.
The mid-infrared emission increases along with $\dot M$, and we conclude that
this is due to an increase in the mass in the inner disk. The cm emission,
which probes the jet, also appears to increase as $\dot M$ increases, and the
changes in the cm flux are consistent with the variability in $\dot M$ assuming
the mass-loss rate is ~10% $\dot M$. The 3 cm emission morphology also appears
changed compared with observations taken three years previously, suggesting
that for the first time, we may be tracking changes in the jet morphology of a
TTS. The X-ray luminosity is constant throughout the three epochs, ruling out
variable high-energy stellar radiation as the cause for the increases in the
mid-infrared or cm emission. Tying together the multiwavelength variability
observed, we conclude that an increase in the surface density in the inner disk
resulted in more mass loading onto the star and therefore a higher $\dot M$,
which led to a higher mass-loss rate in the jet. These results stress the
importance of coordinated multiwavelength work to better understand the
star-disk-jet connection.

Solar and Stellar Astrophysics