The Aromatic Infrared Bands around the Wolf–Rayet Binary WR 140 Revealed by JWST

Abstract We have analyzed the aromatic infrared bands (AIBs) in the 6–11.2 μ m range around the Wolf–Rayet (WR) binary WR 140 ( d = 1.64 kpc) obtained with the James Webb Space Telescope Mid-Infrared Instrument Medium-Resolution Spectrometer (MRS). In WR 140’s circumstellar environment, we have detected AIBs at 6 and 7.7 μ m, which are attributed to C–C stretching modes. These features have been detected in the innermost dust shell (Shell 1; ∼2100 au from WR 140), the subsequent dust shell (Shell 2; ∼5200 au), and “off-shell” regions in the MRS coverage. The 11.2 μ m AIB, which is associated with the C–H out-of-plane bending mode, has been tentatively detected in Shell 2 and the surrounding off-shell positions around Shell 2. We compared the AIB features from WR 140 to spectra of established AIB feature classes A, B, C, and D. The detected features around WR 140 do not agree with these established classes. The peak wavelengths and full width half maxima of the 6 and 7.7 μ m features are, however, consistent with those of R Coronae Borealis stars with hydrogen-poor conditions. We discuss a possible structure of carbonaceous compounds and environments where they form around WR 140. It is proposed that hydrogen-poor carbonaceous compounds initially originate from the carbon-rich WR wind, and the hydrogen-rich stellar wind from the companion O star may provide hydrogen to these carbonaceous compounds.

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Publication Details

Journal
The Astrophysical Journal
Published
2025-10-28
DOI
https://doi.org/10.3847/1538-4357/ae045c
Citations
1
Primary Topic
Astrophysics and Star Formation Studies
Type
article
Field-Weighted Citation Impact
1.15
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article

The Aromatic Infrared Bands around the Wolf–Rayet Binary WR 140 Revealed by JWST

P. M. Williams, Takashi Onaka, Ryan M. Lau, A. F. J. Moffat et al.
1 citations
The Astrophysical Journal
Astrophysics and Star Formation Studies
1.15
article

The Aromatic Infrared Bands around the Wolf–Rayet Binary WR 140 Revealed by JWST

P. M. Williams, Takashi Onaka, Ryan M. Lau, A. F. J. Moffat, Hideo Matsuhara, Thomas Madura, W. W. Duley, G. Weigelt, M. García-Marín, Noel D. Richardson, A. T. Tokunaga, Kotomi Taniguchi, J. Sánchez-Bermúdez, T. R. Gull, Riko Senoo
article en
1 citations

Abstract

Abstract We have analyzed the aromatic infrared bands (AIBs) in the 6–11.2 μ m range around the Wolf–Rayet (WR) binary WR 140 ( d = 1.64 kpc) obtained with the James Webb Space Telescope Mid-Infrared Instrument Medium-Resolution Spectrometer (MRS). In WR 140’s circumstellar environment, we have detected AIBs at 6 and 7.7 μ m, which are attributed to C–C stretching modes. These features have been detected in the innermost dust shell (Shell 1; ∼2100 au from WR 140), the subsequent dust shell (Shell 2; ∼5200 au), and “off-shell” regions in the MRS coverage. The 11.2 μ m AIB, which is associated with the C–H out-of-plane bending mode, has been tentatively detected in Shell 2 and the surrounding off-shell positions around Shell 2. We compared the AIB features from WR 140 to spectra of established AIB feature classes A, B, C, and D. The detected features around WR 140 do not agree with these established classes. The peak wavelengths and full width half maxima of the 6 and 7.7 μ m features are, however, consistent with those of R Coronae Borealis stars with hydrogen-poor conditions. We discuss a possible structure of carbonaceous compounds and environments where they form around WR 140. It is proposed that hydrogen-poor carbonaceous compounds initially originate from the carbon-rich WR wind, and the hydrogen-rich stellar wind from the companion O star may provide hydrogen to these carbonaceous compounds.

The Astrophysical JournalVol. 993(1)
California Institute of Technology (US), Space Telescope Science Institute (US), Goddard Space Flight Center (US), University of Hawaii System (US), University of Waterloo (CA), Universidad Autónoma de la Ciudad de México (MX), National Institutes of Natural Sciences (JP), Japan Aerospace Exploration Agency (JP), Royal Observatory (GB), Community Science and Data Center (US), Centre for Research in Astrophysics of Québec (CA), Institute of Space and Astronautical Science (JP), Max Planck Institute for Radio Astronomy (DE), National Astronomical Observatory of Japan (JP), Infrared Processing and Analysis Center (US), San Jose State University (US), Université de Montréal (CA), The University of Tokyo (JP), Embry–Riddle Aeronautical University (US), Universidad Nacional Autónoma de México (MX), University of Edinburgh (GB)
Openalex Percentile: Top 15%
Astrophysics and Star Formation Studies
1.15
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