Context. Understanding the dispersal of protoplanetary disks remains a central challenge in planet formation theory. Disk winds driven by magnetohydrodynamics (MHD) and/or photoevaporation are now recognized as primary agents of dispersal. With the advent of the James Webb Space Telescope (JWST), spatially resolved imaging of these winds, particularly in H2 pure rotational lines, have become possible, revealing X-shaped morphologies and integrated fluxes of ∼10−16−10−15 erg s−1 cm−2. Aims. However, the lack of theoretical models suitable for direct comparison has limited the interpretation of these features. To address this, we present the first model of photoevaporative H2 winds tailored for direct comparison with JWST observations. Methods. Using radiation hydrodynamics simulations coupled with chemistry, we derived steady-state wind structures and postprocessed them to compute H2-level populations and line radiative transfer, including collisional excitation and spontaneous decay. Results. Our synthetic images reproduce the observed X-shaped morphology with radial extents of ≳50-300 au and semi-opening angles of ∼37°-50°, matching observations of Tau 042021 and SY Cha. While the predicted line fluxes are somewhat lower than the observed values, they remain broadly consistent for lower J transitions despite the model not being specifically tailored to these sources. Conclusions. These results suggest that photoevaporation is a viable mechanism for reproducing key features of observed H2 winds, including morphology and fluxes, though conclusive identification of the wind origin requires source-specific modeling. This conclusion challenges the reliance on geometrical structures alone to distinguish between MHD winds and photoevaporation. Based on our findings, we also discuss alternative diagnostics of photoevaporative winds. This work provides a critical first step toward interpreting spatially resolved H2 winds and motivates future modeling efforts.

Photoevaporation can reproduce extended H2 emission from protoplanetary disks imaged by JWST/MIRI-MRS / R. Nakatani, G. Rosotti, B. Tabone, A. Sellek. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 706:(2026 Feb), pp. A295.1-A295.28. [10.1051/0004-6361/202556740]

Photoevaporation can reproduce extended H2 emission from protoplanetary disks imaged by JWST/MIRI-MRS

R. Nakatani
Primo
;
G. Rosotti;
2026

Abstract

Context. Understanding the dispersal of protoplanetary disks remains a central challenge in planet formation theory. Disk winds driven by magnetohydrodynamics (MHD) and/or photoevaporation are now recognized as primary agents of dispersal. With the advent of the James Webb Space Telescope (JWST), spatially resolved imaging of these winds, particularly in H2 pure rotational lines, have become possible, revealing X-shaped morphologies and integrated fluxes of ∼10−16−10−15 erg s−1 cm−2. Aims. However, the lack of theoretical models suitable for direct comparison has limited the interpretation of these features. To address this, we present the first model of photoevaporative H2 winds tailored for direct comparison with JWST observations. Methods. Using radiation hydrodynamics simulations coupled with chemistry, we derived steady-state wind structures and postprocessed them to compute H2-level populations and line radiative transfer, including collisional excitation and spontaneous decay. Results. Our synthetic images reproduce the observed X-shaped morphology with radial extents of ≳50-300 au and semi-opening angles of ∼37°-50°, matching observations of Tau 042021 and SY Cha. While the predicted line fluxes are somewhat lower than the observed values, they remain broadly consistent for lower J transitions despite the model not being specifically tailored to these sources. Conclusions. These results suggest that photoevaporation is a viable mechanism for reproducing key features of observed H2 winds, including morphology and fluxes, though conclusive identification of the wind origin requires source-specific modeling. This conclusion challenges the reliance on geometrical structures alone to distinguish between MHD winds and photoevaporation. Based on our findings, we also discuss alternative diagnostics of photoevaporative winds. This work provides a critical first step toward interpreting spatially resolved H2 winds and motivates future modeling efforts.
ISM: jets and outflows; photon-dominated region (PDR); protoplanetary disks
Settore PHYS-05/A - Astrofisica, cosmologia e scienza dello spazio
   Rebuilding the foundations of planet formation: proto-planetary disc evolution (DiscEvol)
   DiscEvol
   EUROPEAN COMMISSION
   101039651

   A new window into planet formation: disc kinematics
   FONDAZIONE CARIPLO
   ID Progetto 2022-1217
feb-2026
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1225327
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