Letter to the Editor

Detection of CO₂ ice in the planetary nebula NGC 6302

¹ Department of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada
² Institute for Earth and Space Exploration, University of Western Ontario, London, Ontario, Canada
³ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA, Leiden, The Netherlands
⁴ Space Policy Institute, George Washington University, 20052 Washington, DC, USA
⁵ Cardiff Hub for Astrophysics Research and Technology (CHART), School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK
⁶ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
⁷ Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255, USA
⁸ Department of Astronomy, University of Texas at Austin, Austin, TX 78712, USA
⁹ Department of Physics, Maynooth University, Maynooth, County Kildare, Ireland
¹⁰ Laboratório Nacional de Astrofísica, Rua dos Estados Unidos, 154, Bairro das Nações, Itajubá, MG 37504-365, Brazil
¹¹ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
¹² Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
¹³ Institute for Scientific Research, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA
¹⁴ Center for Imaging Science, Rochester Institute of Technology, Rochester, NY 14623, USA
¹⁵ School of Physics and Astronomy, Rochester Institute of Technology, Rochester, NY 14623, USA
¹⁶ Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, Rochester, NY 14623, USA
¹⁷ Institut de Ciències de l’Espai (ICE, CSIC), Can Magrans, s/n, E-08193 Cerdanyola del Vallès, Barcelona, Spain
¹⁸ ICREA, Pg. Lluís Companys 23, E-08010 Barcelona, Spain
¹⁹ Institut d’Estudis Espacials de Catalunya (IEEC), E-08860 Castelldefels, Barcelona, Spain
²⁰ Instituto de Física e Química, Universidade Federal de Itajubá, Av. BPS 1303 Pinheirinho, 37500-903 Itajubá, MG, Brazil
²¹ Jet Propulsion Laboratory, 4800 Oak Grove Drive, California Institute of Technology, Pasadena, CA 91109, USA
²² University of West Georgia, 1601 Maple Street, Carrollton, GA 30118, USA
²³ European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching, Germany
²⁴ Department of Astrophysics/IMAPP, Radboud University, PO Box 19 9010, 6500 GL, Nijmegen, The Netherlands
²⁵ SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA, Leiden, The Netherlands
²⁶ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, UK

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Received: 26 November 2025
Accepted: 23 February 2026

Abstract

Using JWST/MIRI observations, we report the detection of CO₂ ice in the dusty torus of the planetary nebula NGC 6302, an environment generally considered hostile to fragile molecular species and ices due to intense UV irradiation. This detection accompanies cold (20–50 K) gas-phase CO₂ along the same sightlines. The ice absorption profile exhibits a double-peak profile, which is characteristic of pure crystalline CO₂ ice. The CO₂ gas-to-ice ratio is higher by more than an order of magnitude than in young stellar objects, which indicates distinct ice formation or processing mechanisms in evolved stellar environments. This discovery demonstrates that the dusty torus provides sufficient shielding to harbor ice chemistry, and that ice-mediated surface reactions must be incorporated into chemical models of planetary nebulae.