Some carbon-rich Wolf–Rayet (WC) stars show an infrared excess from dust emission (WCd stars). Dust forms in the collision of the WC wind with a companion star’s wind. As this dust is carried toward the interstellar medium (ISM) at close to the WCd wind speed and the binary continues through its orbit, a spiral structure forms around the system. The shape depends on the orbital eccentricity and period, as well as stellar parameters like mass-loss rates and terminal wind speeds. Imaging of the WCd binary WR 140 with JWST/MIRI revealed 17 concentric dust shells surrounding the binary. We present new JWST imaging of four additional WCd systems (WR 48a, WR 112, WR 125, and WR 137) that were imaged in 2024. In this analysis, we show that the dust is long-lived, detected with an age of at least 130 yr, but more than 300 yr in some systems. Longer-duration measurements are limited by sensitivity. Regular spacing of dust features confirms the periodic nature of dust formation, consistent with a connection to binary motion. We use these images to estimate the proper motion of the dust, finding the dust to propagate out to the ISM with motion comparable to the wind speed of the WC stars. In addition to these results, we observe unusual structures around WR 48a, which could represent dusty clumps shaped by photoevaporation and wind ablation like young proplyd objects. These results demonstrate that WC dust is indeed long-lived and should be accounted for in galactic dust budgets.
Carbon-rich Dust Injected into the Interstellar Medium by Galactic WC Binaries Survives for Hundreds of Years
- Creators
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Richardson, Noel D.1
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Henson, Micaela1
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Lieb, Emma P.2
- Kehl, Corey1
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Lau, Ryan M.3
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Williams, Peredur M.4
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Corcoran, Michael F.5, 6
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Callingham, J. R.7, 8
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Chené, André-Nicolas9
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Gull, Theodore R.5
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Hamaguchi, Kenji5, 10
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Han, Yinuo11
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Hankins, Matthew J.12
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Hill, Grant M.13
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Hoffman, Jennifer L.2
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Mackey, Jonathan14
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Moffat, Anthony F. J.15
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Pope, Benjamin J. S.16
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Pradhan, Pragati1
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Russell, Christopher M. P.17
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Sander, Andreas A. C.18
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St-Louis, Nicole15
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Stevens, Ian R.19
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Tuthill, Peter20
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Weigelt, Gerd21
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White, Ryan M. T.16
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1.
Embry–Riddle Aeronautical University
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2.
University of Denver
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3.
NOIRLab
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4.
Royal Observatory
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5.
Goddard Space Flight Center
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6.
Catholic University of America
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7.
Netherlands Institute for Radio Astronomy
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8.
University of Amsterdam
- 9. NSF's NOIRLab, 670 N. A'ohoku Place, Hilo, HI 96720, USA
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10.
University of Maryland, Baltimore County
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11.
California Institute of Technology
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12.
Arkansas Tech University
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13.
W.M. Keck Observatory
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14.
Dublin Institute For Advanced Studies
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15.
University of Montreal
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16.
Macquarie University
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17.
University of Delaware
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18.
Heidelberg University
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19.
University of Birmingham
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20.
University of Sydney
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21.
Max Planck Institute for Radio Astronomy
Abstract
Copyright and License
© 2025. The Author(s). Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
This material is based upon work supported by NASA under award number 80GSFC24M0006 and based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract number NAS 5-03127 for JWST. These observations are associated with program #4093. Support for program #4093 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127.
N.D.R. is grateful for support from the Cottrell Scholar Award #CS-CSA-2023-143 sponsored by the Research Corporation for Science Advancement. E.P.L. and J.L.H. are grateful for support from a NASA FINESST fellowship under grant #80NSSC24K1547. C.K. acknowledges support from the Embry-Riddle Aeronautical University’s Undergraduate Research Institute. J.R.C. acknowledges funding from the European Union via the European Research Council (ERC) grant Epaphus (project number 101166008). M.F.C. and K.H. are supported by NASA under award number 80GSFC24M0006. A.A.C.S. is supported by the German Deutsche Forschungsgemeinschaft, DFG in the form of an Emmy Noether Research Group—Project-ID 445674056 (SA4064/1-1, PI: Sander). N.S-L. acknowledges financial support from the National Sciences and Engineering Council (NSERC) of Canada.
Facilities
JWST - James Webb Space Telescope (MIRI).
Software References
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Additional details
- National Aeronautics and Space Administration
- 80GSFC24M0006
- National Aeronautics and Space Administration
- NAS 5-03127
- Space Telescope Science Institute
- 4093
- Research Corporation for Science Advancement
- CS-CSA-2023-143
- National Aeronautics and Space Administration
- 80NSSC24K1547
- Embry-Riddle Aeronautical University
- Undergraduate Research Institute
- European Research Council
- Epaphus 101166008
- Deutsche Forschungsgemeinschaft
- SA4064/1-1
- Natural Sciences and Engineering Research Council
- Accepted
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2025-05-29
- Available
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2025-07-07Published
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)
- Publication Status
- Published