Year: 2026
Type: preprint
Abstract: Powerful X-ray flares from young stars may rapidly alter the physical and chemical conditions of their planet-forming disks, but direct observational tests remain scarce. We present a Chandra-JWST/NIRSpec study of infrared spectral variability associated with pre-main-sequence (PMS) X-ray flares in the Orion Nebula. Combining six Chandra/ACIS-I observations with three NIRSpec-MOS visits, we analyze two-epoch spectra of 10 X-ray Flare stars and 12 matched non-flaring Controls among 84 observed disk-bearing PMS stars. We investigate three diagnostics: narrow 2.8-4.3 micron features, HI Br-alpha, and the CO fundamental band. Flare stars show tentative evidence for relatively fewer variable narrow features at longer wavelengths than Controls, while feature incidence decreases strongly with projected distance from the dominant ionizing O star Theta1 Ori C. Most classifiable features appear in absorption. These properties suggest that at least some features may arise in externally irradiated disk atmospheres and/or associated photoevaporative flows, with their apparent epoch-to-epoch variability potentially reflecting spatial sampling of such locally structured material rather than intrinsic temporal changes. Br-alpha behaves differently: flare stars show systematically stronger variability and uniquely exhibit absorption-core profiles, suggesting control by magnetospheric accretion and stellar magnetic processes rather than disk irradiation. The CO fundamental band shows no significant flare-associated variability, consistent with thermochemical models predicting weak responses to moderate X-ray superflares. This pilot study demonstrates the potential of coordinated Chandra-JWST observations to probe how young stellar magnetic activity affects planet-forming environments, motivating future monitoring to build larger superflare samples and extend them into the rare X-ray mega-flare regime.
Source: arXiv (Cornell University)
Authors: Getman, Konstantin V., Luhman, Kevin L., Portilla-Revelo, Bayron, Rab, Christian, Brunn, Valentin, Feigelson, Eric D., Bik, Arjan, Forbrich, Jan, Frediani, Jenny, Haworth, Thomas J., Law, Charles J., Padovani, Marco, Ramirez-Tannus, Maria Claudia, Winter, Andrew J., Airapetian, Vladimir S., Cleeves, L. Ilsedore, Dzib, Sergio A., Kuhn, Michael A., Waggoner, Abygail R., Waters, Rens
Institutions: Pennsylvania State University, Max Planck Institute for Extraterrestrial Physics, Ludwig-Maximilians-Universität München, Arcetri Astrophysical Observatory, National Institute for Astrophysics, Stockholm University, University of Hertfordshire, Queen Mary University of London, University of Minnesota, Max Planck Institute for Astronomy, Goddard Space Flight Center, American University, National Aeronautics and Space Administration, University of Virginia, Max Planck Institute for Radio Astronomy, University of Wisconsin–Madison, Radboud University Nijmegen, Space Research Organisation Netherlands
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222017169