Nested Dust Shells around the Wolf-Rayet Binary WR 140 observed with JWST

Date

2022-10-12

Department

Program

Citation of Original Publication

Lau, R.M., Hankins, M.J., Han, Y. et al. Nested dust shells around the Wolf–Rayet binary WR 140 observed with JWST. Nat Astron (2022). https://doi.org/10.1038/s41550-022-01812-x

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Subject to Springer Nature re-use terms. Non-commercial use only.

Subjects

Abstract

Massive colliding-wind binaries that host a Wolf-Rayet (WR) star present a potentially important source of dust and chemical enrichment in the interstellar medium (ISM). However, the chemical composition and survival of dust formed from such systems is not well understood. The carbon-rich WR (WC) binary WR 140 presents an ideal astrophysical laboratory for investigating these questions given its welldefined orbital period and predictable dust-formation episodes every 7.93 years around periastron passage. We present observations from our Early Release Science program (ERS1349) with the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer (MRS) and Imager that reveal the spectral and spatial signatures of nested circumstellar dust shells around WR 140. MIRI MRS spectroscopy of the second dust shell and Imager detections of over 17 shells formed throughout the past & 130 years confirm the survival of carbonaceous dust grains from WR 140 that are likely carriers of “unidentified infrared” (UIR)-band features at 6.4 and 7.7 µm. The observations indicate that dust-forming WC binaries can enrich the ISM with organic compounds and carbonaceous dust.