  Understanding the temperature structure of protoplanetary disks is key to
interpreting observations, predicting the physical and chemical evolution of
the disk, and modeling planet formation processes. In this study, we constrain
the two-dimensional thermal structure of the disk around Herbig Ae star HD
163296. Using the thermo-chemical code RAC2D, we derive a thermal structure
that reproduces spatially resolved ALMA observations (~0.12 arcsec (13 au) -
0.25 arcsec (26 au)) of CO J = 2-1, 13CO J = 1-0, 2-1, C18O J = 1-0, 2-1, and
C17O J = 1-0, the HD J = 1-0 flux upper limit, the spectral energy distribution
(SED), and continuum morphology. The final model incorporates both a radial
depletion of CO motivated by a time scale shorter than typical CO gas-phase
chemistry (0.01 Myr) and an enhanced temperature near the surface layer of the
the inner disk (z/r <= 0.21). This model agrees with the majority of the
empirically derived temperatures and observed emitting surfaces derived from
the J = 2-1 CO observations. We find an upper limit for the disk mass of 0.35
Msun, using the upper limit of the HD J = 1-0 and J = 2-1 flux. With our final
thermal structure, we explore the impact that gaps have on the temperature
structure constrained by observations of the resolved gaps. Adding a large gap
in the gas and small dust additionally increases gas temperature in the gap by
only 5-10%. This paper is part of the MAPS special issue of the Astrophysical
Journal Supplement.
