Panchromatic JWST Observations and Models of the Dim Type Iax Supernova SN 2024vjm at 200 days
Year: 2026
Type: article
Abstract: We report JWST spectra and photometry of the underluminous Type Iax supernova (SN Iax) 2024vjm obtained 202.8 rest-frame days postexplosion. The spectrum exhibits a rich set of forbidden lines from low-ionization, intermediate-mass, and iron-group elements, notably the [Ni ii ] 6.64 μ m resonance line, which is a direct indicator of stable nickel. Strong CO and SiO emission is detected alongside a warm dust continuum; the spectral properties are consistent with preexisting rather than newly formed dust. Synthetic spectra were computed with the generalized stellar atmospheres code PHOENIX using simplified ejecta models. The models reproduce the overall spectral energy distribution and the molecular emission features reasonably well, but substantially underestimate the strength of the mid-infrared atomic forbidden lines, leaving the synthetic spectrum dominated by molecular emission. Experiments in which the molecular opacity is suppressed do not recover the forbidden lines; instead, the emission peak migrates to Co and Fe transitions near 2 μ m. We attribute this discrepancy to poorly constrained collisional rates and possibly to an excess of iron group material in the current ejecta models. A prominent feature at 12.8 μ m is not well accounted for by the [Ne ii ] 12.81 μ m line, indicating that the 12.8 μ m feature may be largely due to [Fe iii ]. The presence of CO, SiO, and stable nickel together with the nondetection of neon places tight constraints on the total ejecta mass and the nucleosynthetic yields of SN Iax progenitor systems.
Authors: E. Baron, J. M. DerKacy, C. Ashall, M. Shahbandeh, Peter H. Hauschildt, T. Barman, J. P. Aufdenberg, C. R. Burns, N. Morrell, M. D. Stritzinger, P. Hoeflich, K. Medler, E. Fereidouni, C. M. Pfeffer, T. Mera, W. B. Hoogendam, S. Shiber, P. J. Brown, Divya Mishra, Inma Dominguez, L. Galbany, Paolo Mazzali, E. Y. Hsiao, Huangfei Xiao, T. de Jaeger, S. Kumar
Institutions: Planetary Science Institute, Space Telescope Science Institute, University of Hawaiʻi at Mānoa, University of Arizona, Embry–Riddle Aeronautical University, Carnegie Institution for Science, Las Campanas Observatory, Aarhus University, Florida State University, Virginia Tech, Texas A&M University, Universidad de Granada, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Max Planck Institute for Astrophysics, Liverpool John Moores University, Sorbonne Université, University of Virginia
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, University of Oklahoma, Space Telescope Science Institute, National Energy Research Scientific Computing Center, Bundesministerium für Bildung und Forschung, Generalitat de Catalunya, Ministerio de Ciencia e Innovación, Yukawa Institute for Theoretical Physics, Kyoto University, Office of Science, Supercomputing Center for Education and Research, University of Oklahoma, Agencia Estatal de Investigación, European Social Fund
Awards: G103270039, G1338664626, G1398330795, MULTI-MISSION UV/OPTICAL DATA ARCHIVE CENTER, G1643223109, G1809499108, G1855990336, G1873308993, G193590374, G2064873908, G2262748287, G2309174360, G2453247062, G2462415295, G2468512172, G256731684, G2787076192, G2849891921, G2952690682, G3005324705, G300979063, G3388861423, G3439265645, G3459355364, G3480869486, G3518538256, G3534823121, G3614472770, G406396239, G4100987161, G4188109996, G425668148, G430777504, G433322167, G4704197846, G4776629850, G4904421384, G5080475149, Collaborative Research: Unravelling Stripped Supernovae - Synergy between Observations and Modeling, G5421974903, G5568641063, G5805502524, G58316358, G5875372848, G5897425255, G617610489, G6218905885, G6273510985, G6372401702, G6513613686, G6910663132, G6996428894, G7226413692, G7297159037, G7337822738, G7431147399, G743399419, G7679015527, G7730037046, G8099852790, G8107606116, G8182552442, G8302625262, G8324017279, G8376596093, G8511709958, G8717866391, G8862132048, G8969242533, G905898890
OpenAlex ID: W7211893151