The JWST/MIRI view of the planetary nebula NGC 6302 – I. A UV-irradiated torus and a hot bubble triggering PAH formation
Journal article, 2025
NGC 6302 is a spectacular bipolar planetary nebula (PN) whose spectrum exhibitsfast outflows and highly ionized emission lines, indicating the presence of a very hot central star (∼220 000 K). Its infrared spectrum reveals a mixed oxygen and carbon dust chemistry, displaying both silicate and polycyclic aromatic hydrocarbon (PAH) features. Using the James Webb Space Telescope Mid-Infrared Instrument and Medium Resolution Spectrometer, a mosaic map was obtained over the core of NGC 6302, covering the wavelength range of 5–28 μm and spanning an area of ∼18.5 arcsec × 15arcsec. The spatially resolved spectrum reveals ∼200 molecular and ionized lines from species requiring ionization potentials of up to 205 eV. The spatial distributions highlight a complex structure at the nebula’s centre. Highly ionized species such as [Mg VII] and [Si VII] show compact structures, while lower ionization species such as H+ extend much farther outwards, forming filament-defined rims that delineate a bubble. Within the bubble, the H+ and H2 emission coincide, while the PAH emission appears farther out, indicating an ionization structure distinct from typical photodissociation regions, such as the Orion Bar. This may be the first identification of a PAH formation site in a PN. This PN appears to be shaped not by a steady, continuous outflow, but by a series of dynamic, impulsive bubble ejections, creating local conditions conducive to PAH formation. A dusty torus surrounds the core, primarily composed of large (μm-sized) silicate grains with crystalline components. The long-lived torus contains a substantial mass of material, which could support an equilibrium chemistry and a slow dust-formation process.
planetary nebulae: general
ISM: molecules
circumstellar matter
planetary nebulae: individual: NGC 6302
dust, extinction
ISM: atoms
Author
M. Matsuura
Cardiff University
Kevin Volk
Space Telescope Science Institute (STScI)
Patrick Kavanagh
Maynooth University
B. Balick
University of Washington
R. Wesson
University College London (UCL)
Cardiff University
A. Zijlstra
University of Manchester
Macquarie University
Harriet L. Dinerstein
The University of Texas at Austin
Els Peeters
Western University
SETI Institute
N. C. Sterling
University of West Georgia
Jan Cami
Western University
SETI Institute
M. J. Barlow
University College London (UCL)
J. H. Kastner
Rochester Institute of Technology
Jeremy R. Walsh
European Southern Observatory (ESO)
Lbfm Waters
Radboud University
Netherlands Institute for Space Research (SRON)
N. Hirano
Academia Sinica
I. Aleman
Laboratorio Nacional de Astrofisica, Itajuba
J. Bernard-Salas
Innovative Common Laboratory For Space Spectroscopy (INCLASS)
Observatoire de la Cote d'Azur
Charmi Bhatt
Western University
Jadl Blommaert
Vrije Universiteit Brussel (VUB)
Nicholas Clark
Western University
O. C. Jones
Royal Observatory
Kay Justtanont
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
F. Kemper
Spanish National Research Council (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Catalan Institution for Research and Advanced Studies
Kathleen E. Kraemer
Boston College
E. Lagadec
Observatoire de la Cote d'Azur
J. Martin Laming
Naval Research Laboratory
F. J. Molster
Leidse instrumentmakers School
Paula Moraga Baez
Rochester Institute of Technology
Hektor Monteiro
Federal University of Itajubá
Cardiff University
A.M.S. Richards
University of Manchester
R. Sahai
California Institute of Technology (Caltech)
G. C. Sloan
Space Telescope Science Institute (STScI)
The University of North Carolina System
Maryam Torki
Spanish National Research Council (CSIC)
Catalan Institution for Research and Advanced Studies
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
P. A. M. van Hoof
Royal Observatory of Belgium
Nicholas J. Wright
Keele University
Finnbar Wilson
Cardiff University
Alexander Csukai
University of Manchester
Monthly Notices of the Royal Astronomical Society
00358711 (ISSN) 13652966 (eISSN)
Vol. 542 2 1287-1307Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Astronomy, Astrophysics, and Cosmology
DOI
10.1093/mnras/staf1194
Related datasets
DOI: http://archive.stsci.edu/doi/resolve/resolve.html?doi=10.17909/s1rn-1t84 URI: https://mast.stsci.edu/