A Search for Spatially Resolved Infrared Ro-Vibrational Molecular Hydrogen Emission from the Disks of Young Stars

Abstract

We present results from a survey searching for spatially resolved near-infrared line emission from molecular hydrogen gas in the circumstellar environments of nine young stars: AA Tau, AB Aur, DoAr 21, GG Tau, GM Aur, LkCa 15, LkH$\alpha$ 264, UY Aur, and V773 Tau. Prior high-resolution spectra of these stars showed the presence of ro-vibrational H${}_2$ line emission at 2.12$\mu$m with characteristics more typical of gas located in proto-planetary disks rather than outflows. In this study, we spatially resolve the H${}_2$ emission in the eight stars where it is detected. LkCa 15 is the only target that exhibits no appreciable H${}_2$ despite a prior detection. We find an anti-correlation between H${}_2$ and X-ray luminosities, likely indicating that the X-ray ionization process is not the dominant H${}_2$ excitation mechanism in these systems. AA Tau, UY Aur, and V773 Tau show discrete knots of H${}_2$, as typically associated with shocks in outflowing gas. UY Aur and V773 Tau exhibit spatially resolved velocity structures, while the other systems have spectrally unresolved emission consistent with systemic velocities. V773 Tau exhibits a complex line morphology indicating the presence of multiple excitation mechanisms, including red and blue-shifted bipolar knots of shock-excited outflowing gas. AB Aur, GM Aur, and LkH$\alpha$ 264 have centralized, yet spatially resolved H${}_2$ emission consistent with a disk origin. The H${}_2$ images of AB Aur reveal spiral structures within the disk, matching those observed in ALMA CO maps. This survey reveals new insights into the structure and excitation of warm gas in the circumstellar environments of these young stars.

39 pages, 20 figures. Accepted for Publication in the ApJ

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Cited by in corpus (13)

• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• Gravitational instability in a planet-forming disk
• JWST/NIRSpec Reveals the Nested Morphology of Disk Winds from Young Stars
• GIARPS High-resolution Observations of T Tauri stars (GHOsT). II. Connecting atomic and molecular winds in protoplanetary disks
• Mapping the merging zone of late infall in the AB Aur planet-forming system
• Interpreting molecular hydrogen and atomic oxygen line emission of T Tauri disks with photoevaporative disk-wind models
• PENELLOPE IV. A comparison between optical forbidden lines and ${\mathrm{H}}_2$ UV lines in the Orion OB1b and $\sigma$-Ori associations
• X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr~A*
• Study of the bipolar jet of the YSO Th 28 with VLT/SINFONI: Jet morphology and H${}_2$ emission
• Photoevaporation Can Reproduce Extended ${\mathrm{H}}_2$ Emission from Protoplanetary Disks Imaged by JWST MIRI
• Spatially resolved velocity structure in jets of DF Tau and UY Aur A
• The role of detailed gas and dust opacities in shaping the evolution of the inner disc edge subject to episodic accretion
• Molecules with ALMA at Planet-forming Scales (MAPS) XII: Inferring the C/O and S/H ratios in Protoplanetary Disks with Sulfur Molecules