Observational Signatures of Disk Winds in Protoplanetary Disks: Differentiating Magnetized and Photoevaporative Outflows with Fully Coupled Thermochemistry

Abstract Magnetized winds and photoevaporative winds are critical in shaping protoplanetary disk evolution. Using 2D axisymmetric (magneto)hydrodynamic simulations with fully coupled thermochemistry, we investigate the signatures of the two winds in CO and [C I ] Atacama Large Millimeter/submillimeter Array (ALMA) observations, and examine the potential to distinguish the origins. Our simulations reveal fundamental differences between the two winds: magnetized winds are colder and denser, exhibiting super-Keplerian rotation with small poloidal velocities of ≲1 km s −1 in the atmosphere ( z / R ≳ 0.45), while photoevaporative winds are hotter and less dense, exhibiting sub-Keplerian rotation with higher poloidal velocities of several kilometers per second. In addition to previously identified factors like thermal pressure gradient and disk’s self-gravity, we demonstrate that magnetic force and advection significantly influence rotational velocities of the gas in the wind, which lead to emission patterns that are distinct from Keplerian rotation in synthetic ALMA observations. Magnetized winds are visible in CO channel maps when wind loss rates are ≳10 −8 M ⊙ yr −1 . When wind loss rates are lower, magnetized winds produce subtle perturbations that resemble those produced by protoplanets. While strong X-ray and ultraviolet radiation photodissociates CO in photoevaporative winds, they can create observable ring-like substructures at disk surfaces. [C I ] emission is optically thin and could be most effective at detecting both winds in disks with high gas mass and/or high [C I ] abundance. Due to the spatially extended nature of the winds, using a large beam ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≃</mml:mo> <mml:mn>0</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> <mml:mn>4</mml:mn> </mml:math> for disks in nearby star-forming regions) will be helpful regardless of the tracer used.