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We present Atacama Large Millimeter Array (ALMA) observations of$^{12}$CO2$-$1 emission from circumstellar material around the massive star$\eta$~Carinae. These observations reveal new structural details about the coolequatorial torus located $\sim$4000 au from the star. The CO torus is not acomplete azimuthal loop, but rather, is missing its near side, which appears tohave been cleared away. The missing material matches the direction of apastronin the eccentric binary system, making it likely that $\eta$~Car's companionplayed an important role in disrupting portions of the torus soon afterejection. Molecular gas seen in ALMA data aligns well with the cool dust around$\eta$~Car previously observed in mid-infrared (IR) maps, whereas hot dustresides at the inner surface of the molecular torus. The CO also coincides withthe spatial and velocity structure of near-IR H$_2$ emission. Together, thesesuggest that the CO torus seen by ALMA is actually the pinched waist of theHomunculus polar lobes, which glows brightly because it is close to the starand warmer than the poles. The near side of the torus appears to be a blowout,associated with fragmented equatorial ejecta. We discuss implications for theorigin of various features northwest of the star. CO emission from the maintorus implies a total gas mass in the range of 0.2-1 $M_{\odot}$ (possibly upto 5 $M_{\odot}$ or more, although with questionable assumptions). Deeperobservations are needed to constrain CO emission from the cool polar lobes.

A disrupted molecular torus around Eta Carinae as seen in 12CO with ALMA