Detection of CO₂ ice in the planetary nebula NGC 6302

C. Bhatt (Univ. of Western Ontario), S.W. Cao (Univ. of Western Ontario), J. Cami (Univ. of Western Ontario), N. Clark (Univ. of Western Ontario), P. Ehrenfreund (Leiden Univ.), E. Peeters (Univ. of Western Ontario), M. Matsuura (Cardiff Univ.), G.C. Sloan (STScI, UNC), H.L. Dinerstein (Univ. of Texas Austin), P. Kavanagh (Maynooth Univ.), K. Volk (STScI), I. Aleman (Lab. Nac. Astrof. Brazil), M.J. Barlow (UC London), K. Justannont (Chalmers Univ. of Tech.), K.E. Kraemer (Boston College), J.H. Kastner (Rochester Inst. of Tech.), F. Kemper (ICE, CSIC, IEEC in Barcelona), H. Monteiro (Cardiff Univ., Univ. Fed. Itajuba), R. Sahai (JPL), N.C. Sterling (Univ. of W. Georgia), J.R. Walsh (ESO), L.B.F.M. Waters (Radboud Univ., SRON), A.A. Zijlstra (Univ. of Manchester)

2026, A&A, in press

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, a characteristic of pure, crystalline CO₂ ice. The CO₂ gas-to-ice ratio is more than an order of magnitude higher than in young stellar objects, pointing to distinct ice formation or processing mechanisms in evolved stellar environments. This discovery demonstrates that the dusty torus provides sufficient shielding to harbour ice chemistry, and that ice-mediated surface reactions must be incorporated into chemical models of planetary nebulae.

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Last modified 27 February, 2026. © Gregory C. Sloan and others.