MINDS. The Detection of 13CO2 with JWST-MIRI Indicates Abundant CO2 in a Protoplanetary Disk

Sierra L. Grant*, Ewine F. van Dishoeck, Benoît Tabone, Danny Gasman, Thomas Henning, Inga Kamp, Manuel Güdel, Pierre Olivier Lagage, Giulio Bettoni, Giulia Perotti, Valentin Christiaens, Matthias Samland, Aditya M. Arabhavi, Ioannis Argyriou, Alain Abergel, Olivier Absil, David Barrado, Anthony Boccaletti, Jeroen Bouwman, Alessio Caratti o GarattiVincent Geers, Adrian M. Glauser, Rodrigo Guadarrama, Hyerin Jang, Jayatee Kanwar, Fred Lahuis, Maria Morales-Calderón, Michael Mueller, Cyrine Nehmé, Göran Olofsson, Eric Pantin, Nicole Pawellek, Tom P. Ray, Donna Rodgers-Lee, Silvia Scheithauer, Jürgen Schreiber, Kamber Schwarz, Milou Temmink, Bart Vandenbussche, Marissa Vlasblom, L. B. F. M. Waters, Gillian Wright, Luis Colina, Thomas R. Greve, Kay Justannont, Göran Östlin

*Corresponding author for this work

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We present JWST-MIRI Medium Resolution Spectrometer (MRS) spectra of the protoplanetary disk around the low-mass T Tauri star GW Lup from the MIRI mid-INfrared Disk Survey Guaranteed Time Observations program. Emission from 12CO213CO2, H2O, HCN, C2H2, and OH is identified with 13CO2 being detected for the first time in a protoplanetary disk. We characterize the chemical and physical conditions in the inner few astronomical units of the GW Lup disk using these molecules as probes. The spectral resolution of JWST-MIRI MRS paired with high signal-to-noise data is essential to identify these species and determine their column densities and temperatures. The Q branches of these molecules, including those of hot bands, are particularly sensitive to temperature and column density. We find that the 12CO2 emission in the GW Lup disk is coming from optically thick emission at a temperature of ∼400 K. 13CO2 is optically thinner and based on a lower temperature of ∼325 K, and thus may be tracing deeper into the disk and/or a larger emitting radius than 12CO2. The derived N CO 2 / N H 2 O ratio is orders of magnitude higher than previously derived for GW Lup and other targets based on Spitzer-InfraRed-Spectrograph data. This high column density ratio may be due to an inner cavity with a radius in between the H2O and CO2 snowlines and/or an overall lower disk temperature. This paper demonstrates the unique ability of JWST to probe inner disk structures and chemistry through weak, previously unseen molecular features.

Original languageEnglish
Article numberL6
Number of pages13
JournalAstrophysical Journal Letters
Issue number1
Publication statusPublished - 10-Apr-2023

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