Year: 2025
Type: article
Abstract: We present JWST-MIRI Medium Resolution Spectrometer observations of the Classical T Tauri stars GM Aur and RX J1615.3-3255 (J1615), both hosting transitional disks. Despite their similar stellar and disk properties, the two systems differ strikingly in their carbon-bearing molecular emission. Using local thermodynamic equilibrium slab models to analyze spectral lines within the 13.6–17.7 μ m wavelength range, we find that J1615 exhibits strong emission from H 2 O, HCN, C 2 H 2 , 12 CO 2 , 13 CO 2 , OH, and 13 C 12 CH 2 , whereas GM Aur shows only H 2 O and OH. We measure the accretion rates of both objects using contemporaneous optical spectra and find that J1615’s accretion rate is lower than that of GM Aur. We constrain the properties of the dust in both disks using spectral energy distribution modeling and find elevated amounts of crystalline silicates and larger dust grains in the disk of J1615. The enhanced carbon emission in J1615 may result from a combination of lower accretion rate and larger and more processed dust grains in the inner disk, conditions that together may allow for carbon-rich gas to persist and be detected. These results expand the sample of protoplanetary disks around solar-mass stars with strong CO 2 and C 2 H 2 emission and identify J1615 as a carbon-rich transitional disk, providing new insights into the chemical diversity of planet-forming environments.
Source: The Astronomical Journal
Institutions: Boston University, Carnegie Institution for Science, Earth and Planets Laboratory, Chulalongkorn University, Leiden University, Leiden Observatory, Centre National de la Recherche Scientifique, Université Paris-Saclay, Institut d'Astrophysique Spatiale, University of Michigan, Stony Brook University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Award: G5503445741
OpenAlex ID: W4417436830