  During the main phase of evolution of a protoplanetary disk, accretion
regulates the inner-disk properties, such as the temperature and mass
distribution, and in turn, the physical conditions associated with planet
formation. The driving mechanism behind accretion remains uncertain; however,
one promising mechanism is the removal of a fraction of angular momentum via a
magnetohydrodynamic (MHD) disk wind launched from the inner tens of
astronomical units of the disk. This paper utilizes CO isotopologue emission to
study the unique molecular outflow originating from the HD 163296
protoplanetary disk obtained with the Atacama Large Millimeter/submillimeter
Array. HD~163296 is one of the most well-studied Class II disks and is proposed
to host multiple gas-giant planets. We robustly detect the large-scale rotating
outflow in the 12CO J=2-1 and the 13CO J=2-1 and J=1-0 transitions. We
constrain the kinematics, the excitation temperature of the molecular gas, and
the mass-loss rate. The high ratio of the rates of ejection to accretion (5 -
50), together with the rotation signatures of the flow, provides solid evidence
for an MHD disk wind. We find that the angular momentum removal by the wind is
sufficient to drive accretion through the inner region of the disk; therefore,
accretion driven by turbulent viscosity is not required to explain HD~163296's
accretion. The low temperature of the molecular wind and its overall kinematics
suggest that the MHD disk wind could be perturbed and shocked by the previously
observed high-velocity atomic jet. This paper is part of the MAPS special issue
of the Astrophysical Journal Supplement.
