Exploring dust growth in the episodic WCd system WR140

Abstract

The wind collision region (WCR) in a colliding wind binary (CWB) is a particularly violent place, as such, it is surprising that it is also a region where significant quantities of interstellar dust can form. In extreme cases, approximately 30% of the total mass loss rate of a system can be converted into dust. These regions are poorly understood, as observation and simulation of these systems are difficult. In our previous paper we simulated dust growth in CWB systems using an advected scalar model and found our model to be suitable for qualitative study. For this paper we simulated the periodic dust forming CWB (WCd) system WR140 with our dust model, to determine how dust growth changes over the systems periastron passage. We found that dust production increases significantly at periastron passage, which is consistent with IR emission of the surrounding dusty shell. We also find that the dust production rate of the system decreases rapidly as the stars recede from each other, though the rate of decrease is significantly lower than the rate of increase during periastron passage. This was found to be due to strong cooling and its associated thermal instabilities, resulting in cool, high-density pockets of gas in the WCR where dust forms. The WCR also shows a degree of hysteresis, resulting in a radiative post-shock flow even when the stars are separated enough for the region to behave adiabatically.

9 pages, 9 figures, 5 tables

References in corpus (7)

• The Athena++ Adaptive Mesh Refinement Framework: Design and Magnetohydrodynamic Solvers
• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• Revisiting the Impact of Dust Production from Carbon-Rich Wolf-Rayet Binaries
• The Keck Aperture Masking Experiment: Near-Infrared Sizes of Dusty Wolf-Rayet Stars
• The orbit and stellar masses of the archetype colliding-wind binary WR 140
• Competitive X-ray and Optical Cooling in the Collisionless Shocks of WR 140

Cited by in corpus (5)

• Nested Dust Shells around the Wolf-Rayet Binary WR 140 observed with JWST
• Dynamic Imprints of Colliding-wind Dust Formation from WR140
• From Dust to Nanodust: Resolving Circumstellar Dust from the Colliding-Wind Binary Wolf-Rayet (WR) 140
• Inverse Compton cooling of thermal plasma in colliding-wind binaries
• A multi-ion non-equilibrium solver for ionised astrophysical plasmas with arbitrary elemental abundances