Dust in RCW 58: Clues to common envelope channel formation?

ABSTRACT We present a characterization of the dust in Wolf–Rayet (WR) nebula RCW 58 around WN8h star WR 40 using archival infrared (IR) observations from WISE and Herschel radio ATCA. selected two clumps, free contamination material along line sight located towards southern regions 58, as representative general properties this nebula. Their optical, IR, are then modelled photoionization code cloudy, which calculates self-consistent spatial distribution gas properties. Two populations grains required to model IR SED: population small with sizes 0.002–0.01 $\mu$m, is found throughout large grains, up 0.9 further star. Moreover, clumps have very high dust-to-gas ratios, challenge for their origin. Our supports hypothesis that distributed ring-like structure rather than shell, we estimate mass ∼2.5 M⊙. This suggests progenitor was about $\approx 40^{+2}_{-3}$ The ring morphology, low nebular mass, grain size, ratio lead us propose has formed through common envelope channel, similar what been proposed M 1-67.