Orbitally modulated dust formation by the WC7 O5 colliding-wind binary WR140 - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado




Orbitally modulated dust formation by the WC7 O5 colliding-wind binary WR140 - Astrophysics > Solar and Stellar Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We present high-resolution infrared 2-18 micron images of the archetypalperiodic dust-making Wolf-Rayet binary system WR140 HD 193793 taken between2001 and 2005, and multi-colour J - 19.5 photometry observed between 1989and 2001. The images resolve the dust cloud formed by WR140 in 2001, allowingus to track its expansion and cooling, while the photometry allows tracking theaverage temperature and total mass of the dust. The combination of the twodatasets constrains the optical properties of the dust. The most persistentdust features, two concentrations at the ends of a `bar- of emission to thesouth of the star, were observed to move with constant proper motions of324+-8 and 243+-7 mas-y. Longer wavelength 4.68-micron and 12.5-micronimages shows dust emission from the corresponding features from the previous1993 periastron passage and dust-formation episode. A third persistent dustconcentration to the east of the binary the `arm- was found to have a propermotion ~ 320 mas-y. Extrapolation of the motions of the concentrations back tothe binary suggests that the eastern `arm- began expansion 4-5 months earlierthan those in the southern `bar-, consistent with the projected rotation of thebinary axis and wind-collision region WCR on the sky. Comparison of modeldust images and the observations constrain the intervals when the WCR wasproducing sufficiently compressed wind for dust nucleation in the WCR, andsuggests that the distribution of this material was not uniform about the axisof the WCR, but more abundant in the following edge in the orbital plane.



Autor: P. M. Williams 1, S. V. Marchenko 2, A. P. Marston 3 and 4, A. F. J. Moffat 5, W. P. Varricatt 6, S. M. Dougherty 7, M. R. Kidger

Fuente: https://arxiv.org/



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