From Young to Older Disks: JWST/MIRI Evidence for Fading Molecular Emission and Hints for Elevated C/O in Upper Scorpius

arXiv:2606.27477 · astro-ph.EP, astro-ph.GA · Submitted 2026-06-25 · Read on arXiv

Chengyan Xie, Ilaria Pascucci, Feng Long, Uma Gorti, Andrea Banzatti, Richard Booth, Klaus Pontoppidan, Tamara Molyarova, John Carpenter, Min Fang, Yao Liu, Eshan Raul, Ke Zhang, Steve Ertel, Jordan Stone, Aaron Empey, Carlo F. Manara, Paola Pinilla, Colette Salyk, Benoit Tabone, Miguel Vioque, Lucas Cieza, Giovanni Rosotti, James Miley, Geoffrey A. Blake, Abygail Waggoner

astro-ph.EP, astro-ph.GA

Submitted: 2026-06-25

Comments: 33 pages, 19 figures, 7 tables, accepted by AJ

License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Terminology

• Molecular Rich — 10× in this paper
• Molecular Poor — 8× in this paper
• Consistency — 4× in this paper · explained in 3 episodes
• Trace — 4× in this paper · explained in 2 episodes
• Abundance — 3× in this paper · explained in 1 episode
• Core — 3× in this paper · explained in 2 episodes
• Aperture — 2× in this paper · explained in 1 episode
• James Webb Space Telescope — 2× in this paper
• Calibration — 1× in this paper · explained in 7 episodes
• Degeneracy — 1× in this paper · explained in 3 episodes
• Elias — 1× in this paper · explained in 2 episodes
• General Observer — 1× in this paper
• Large Binocular Telescope Interferometer — 1× in this paper
• University College Dublin — 1× in this paper

Sources

• Molecular diagnostics for the mid-infrared emission of planet-forming disks. Carbon and oxygen elemental abundances
• The JDISC Survey: Linking the Physics and Chemistry of Inner and Outer Protoplanetary Disk Zones
• JWST-DECO: The Impact of Accretion on Mid-Infrared Observable Water in Planet-forming Disks
• Models of the Structure and Evolution of Protoplanetary Disks
• Accretion Variability as a Guide to Stellar Mass Assembly
• A transition from H$_2$O to C$_2$H$_2$ dominated spectra with decreasing stellar luminosity
• Protoplanetary disk cavities with JWST-MIRI: a dichotomy in molecular emission
• Demographics of young stars and their protoplanetary disks: lessons learned on disk evolution and its connection to planet formation
• Improving Accretion Diagnostics for Young Stellar Objects with Mid-infrared Hydrogen lines from JWST/MIRI

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