A three-dimensional view of Gomez’s hamburger

Unravelling the three-dimensional physical structure, the temperature and density distribution, of protoplanetary discs is an essential step if we are to confront simulations of embedded planets or dynamical instabilities. In this paper, we focus on submillimeter array observations of the edge-on source, Gomez’s Hamburger, believed to host an overdensity hypothesized to be a product of gravitational instability in the disc, GoHam b. We demonstrate that, by leveraging the well-characterized rotation of a Keplerian disc to deproject observations of molecular lines in position-position-velocity space into disc-centric coordinates, we are able to map out the emission distribution in the (r,z) plane and (⁠x,|y|,z) space. We show that 12CO traces an elevated layer of z/r∼0.3⁠, while 13CO traces deeper in the disc at z/r≲0.2⁠. We identify an azimuthal asymmetry in the deprojected 13CO emission coincident with GoHam b at a polar angle of ≈30○. At the spatial resolution of ∼1.5 arcsec, GoHam b is spatially unresolved, with an upper limit to its radius of <190 au.