XUE. ProDiMo models of internally and externally irradiated planet-forming disks around 0.3-4.0 solar mass stars (The IRIS project I)
Year: 2026
Type: preprint
Abstract: Most stars and planets form in massive star-forming regions, where disks are exposed to external far-ultraviolet (FUV) radiation from nearby O- and B-type stars. The combined effects of stellar irradiation and external FUV fields on terrestrial planet-forming regions (< 10 au) across stellar masses remain unclear. We investigate how internal UV and X-ray irradiation and external FUV fields affect mid-infrared (mid-IR) gas emission and the atmospheric carbon-to-oxygen (C/O) ratios inferred in T Tauri and Herbig Ae/Be disks. We compute disk structures with ProDiMo and synthetic spectra with FLiTs, convolved to a representative JWST/MIRI-MRS resolution (R$\sim$2680). (1) We present the Internal and external irRadIation of diSks (IRIS) grid: four model sets spanning stellar masses of 0.3-4.0 solar masses, including stellar X-ray flares and an external FUV field of 1e4 G0 (Habing units). (2) We predict increasing flux densities with stellar mass for key atomic and molecular mid-IR tracers. (3) External FUV irradiation enhances CH3+ and H2 emission, whereas FUV-induced disk truncation yields inner disk chemistry resembling that of disks irradiated only by their host stars. (4) Mid-IR H2O, CO2, and C2H2 line ratios imply carbon-rich compositions (C/O$\sim$1-10) in the warm emitting layers of T Tauri and Herbig Ae/Be disks, primarily reflecting stellar irradiation, with little sensitivity to external FUV irradiation. The IRIS grid provides a flexible framework for interpreting JWST and future Extremely Large Telescope (ELT) infrared disk observations across a broad range of stellar properties and irradiation conditions. Future models should include FUV-driven photoevaporative winds, X-ray radiative transfer, and time-dependent X-ray irradiation.
Source: arXiv (Cornell University)
Authors: Frediani, Jenny, Getman, Konstantin V., Woitke, Peter, Portilla-Revelo, Bayron, Feigelson, Eric D., Rab, Christian, Bik, Arjan, Ramírez-Tannus, María Claudia, Waters, Rens, Henning, Thomas, Kamp, Inga, Chaparro, Germán, Hernández, Sebastián, Rodríguez, Simón, Cuartas-Restrepo, Pablo, Winter, Andrew, Haworth, Thomas J., Preibisch, Thomas, van Terwisga, Sierk E., Roccatagliata, Veronica, Brandeker, Alexis
Institutions: Stockholm University, AlbaNova, Pennsylvania State University, Austrian Academy of Sciences, Space Research Institute, Max Planck Institute for Extraterrestrial Physics, Ludwig-Maximilians-Universität München, Max Planck Institute for Astronomy, Radboud University Nijmegen, University of Groningen, Universidad de Antioquia, Queen Mary University of London, Excellence Cluster Origins, Arcetri Astrophysical Observatory, National Institute for Astrophysics, University of Bologna
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G119436362, G2340603345, European Project on Mendelian Forms of Parkinson’s Disease, FOR 2634: Übergangsscheiben: Zeugen der Planetenentstehung, G4066435496, Physics and Chemistry of Planet-Forming Disks in Extreme Radiation Environments, EXC 2094: ORIGINS: Vom Ursprung des Universums bis zu den ersten Bausteinen des Lebens
OpenAlex ID: W7212058132