Stagnant Shells in the Vicinity of the Dusty Wolf-Rayet-OB Binary WR 112
We present high spatial resolution mid-infrared images of the nebula around the late-type carbon-rich Wolf-Rayet (WC)-OB binary system WR 112 taken by the recently upgraded VLT spectrometer and imager for the mid-infrared (VISIR) with the PAH1, Ne ii-2, and Q3 filters. The observations reveal a morp...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/379927 |
| Acceso en línea: | http://hdl.handle.net/10261/379927 |
| Access Level: | acceso abierto |
| Palabra clave: | Infrared: stars Stars: individual (WR 112) Stars: winds, outflows Stars: Wolf–Rayet |
| Sumario: | We present high spatial resolution mid-infrared images of the nebula around the late-type carbon-rich Wolf-Rayet (WC)-OB binary system WR 112 taken by the recently upgraded VLT spectrometer and imager for the mid-infrared (VISIR) with the PAH1, Ne ii-2, and Q3 filters. The observations reveal a morphology resembling a series of arc-like filaments and broken shells. Dust temperatures and masses are derived for each of the identified filamentary structures, which exhibit temperatures ranging from K at the exterior W2 filament to K in the central 3″. The total dust mass summed over the features is 2.6 ± 0.4 × 10 M. A multi-epoch analysis of mid-IR photometry of WR 112 over the past ∼20 years reveals no significant variability in the observed dust temperature and mass. The morphology of the mid-IR dust emission from WR 112 also exhibits no significant expansion from imaging data taken in 2001, 2007, and 2016, which disputes the current interpretation of the nebula as a high expansion velocity (∼1200 km s) "pinwheel"-shaped outflow driven by the central WC-OB colliding-wind binary. An upper limit of ≲120 km s is derived for the expansion velocity assuming a distance of 4.15 kpc. The upper limit on the average total mass-loss rate from the central 3″ of WR 112 is estimated to be ≲8 × 10 M year. We leave its true nature as an open question, but propose that the WR 112 nebula may have formed in the outflow during a previous red or yellow supergiant phase of the central Wolf-Rayet star. © 2017. The American Astronomical Society. |
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