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

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Ryan M. Lau Matthew J. Hankins Yinuo Han Ioannis Argyriou Michael F. Corcoran Jan J. Eldridge Izumi Endo Ori D. Fox Macarena Garcia Marin Theodore R. Gull Olivia C. Jones Kenji Hamaguchi Astrid Lamberts David R. Law Thomas Madura Sergey V. Marchenko Hideo Matsuhara Anthony F. J. Moffat Mark R. Morris Patrick W. Morris

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 well-defined 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 $\gtrsim130$ 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 $\mu$m. The observations indicate that dust-forming WC binaries can enrich the ISM with organic compounds and carbonaceous dust.

Peer Review Status:Awaiting Review

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