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   https://doi.org/10.3847/1538-3881/ab5f15  

   Stefansson, Gudmundur; Cañas, Caleb; Wisniewski, John; Robertson, Paul; Mahadevan, Suvrath; Maney, Marissa; Kanodia, Shubham; Beard, Corey; Bender, Chad F.; Brunt, Peter; et al (March 2020, The Astronomical Journal)
2. Shaping the Future of Critical Zone Science: Advancing Transdisciplinary and Interagency Collaboration for a Resilient Planet

   Perdrial, Julia; Berhe, Asmeret; Aronson, Emma (December 2024, AGU)
3. Water Shielding in the Terrestrial Planet-forming Zone: Implication for Inner Disk Organics

   https://doi.org/10.3847/2041-8213/ac822b  

   Duval, Sara E.; Bosman, Arthur D.; Bergin, Edwin A. (July 2022, The Astrophysical Journal Letters)

   Abstract The chemical composition of the inner region of protoplanetary disks can trace the composition of planetary-building material. The exact elemental composition of the inner disk has not yet been measured and tensions between models and observations still exist. Recent advancements have shown UV shielding to be able to increase the emission of organics. Here, we expand on these models and investigate how UV shielding may impact chemical composition in the inner 5 au. In this work, we use the model from Bosman et al. and expand it with a larger chemical network. We focus on the chemical abundances in the upper disk atmosphere where the effects of water UV shielding are most prominent and molecular lines originate. We find rich carbon and nitrogen chemistry with enhanced abundances of C₂H₂, CH₄, HCN, CH₃CN, and NH₃by >3 orders of magnitude. This is caused by the self-shielding of H₂O, which locks oxygen in water. This subsequently results in a suppression of oxygen-containing species like CO and CO₂. The increase in C₂H₂seen in the model with the inclusion of water UV shielding allows us to explain the observed C₂H₂abundance without resorting to elevated C/O ratios as water UV shielding induced an effectively oxygen-poor environment in oxygen-rich gas. Thus, water UV shielding is important for reproducing the observed abundances of hydrocarbons and nitriles. From our model result, species like CH₄, NH₃, and NO are expected to be observable with the James Webb Space Telescope (JWST). 

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4. Water UV-shielding in the Terrestrial Planet-forming Zone: Implications from Water Emission

   https://doi.org/10.3847/2041-8213/ac66ce  

   Bosman, Arthur D.; Bergin, Edwin A.; Calahan, Jenny; Duval, Sara E. (May 2022, The Astrophysical Journal Letters)

   Abstract Mid-infrared spectroscopy is one of the few ways to observe the composition of the terrestrial planet-forming zone, the inner few astronomical units, of protoplanetary disks. The species currently detected in the disk atmosphere, for example, CO, CO₂, H₂O, and C₂H₂, are theoretically enough to constrain the C/O ratio on the disk surface. However, thermochemical models have difficulties in reproducing the full array of detected species in the mid-infrared simultaneously. In an effort to get closer to the observed spectra, we have included water UV-shielding as well as more efficient chemical heating into the thermochemical code Dust and Lines. We find that both are required to match the observed emission spectrum. Efficient chemical heating, in addition to traditional heating from UV photons, is necessary to elevate the temperature of the water-emitting layer to match the observed excitation temperature of water. We find that water UV-shielding stops UV photons from reaching deep into the disk, cooling down the lower layers with a higher column. These two effects create a hot emitting layer of water with a column of 1–10 × 10¹⁸cm⁻². This is only 1%–10% of the water column above the dustτ= 1 surface at mid-infrared wavelengths in the models and represents <1% of the total water column. 

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5. A Harsh Test of Far-field Scrambling with the Habitable-zone Planet Finder and the Hobby–Eberly Telescope

   https://doi.org/10.3847/1538-4357/abec83  

   Kanodia, Shubham; Halverson, Samuel; Ninan, Joe P.; Mahadevan, Suvrath; Stefansson, Gudmundur; Roy, Arpita; Ramsey, Lawrence W.; Bender, Chad F.; Janowiecki, Steven; Cochran, William D.; et al (April 2021, The Astrophysical Journal)

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