The Wolf-Rayet nebula M 1-67 around WR 124 is located above the Galactic plane in a region mostly empty of interstellar medium , which makes it the perfect target to study the mass-loss episodes associated with the late stages of massive star evolution .
Archive photometric observations from WISE , Spitzer ( MIPS ) and Herschel ( PACS and SPIRE ) are used to construct the spectral energy distribution ( SED ) of the nebula in the wavelength range of 12–500 \mu m. The infrared ( photometric and spectroscopic ) data and nebular optical data from the literature are modeled simultaneously using the spectral synthesis code Cloudy , where the free parameters are the gas density distribution and the dust grain size distribution .
The infrared SED can be reproduced by dust grains with two size distributions : a MRN power-law distribution with grain sizes between 0.005 and 0.05 \mu m and a population of large grains with representative size 0.9 \mu m. The latter points towards an eruptive origin for the formation of M 1-67 .
The model predicts a nebular ionized gas mass of M _ { \mathrm { ion } } = 9.2 ^ { +1.6 } _ { -1.5 } ~ { } \mathrm { M } _ { \odot } and the estimated mass-loss rate during the dust-formation period is \dot { M } \approx 6 \times 10 ^ { -4 } ~ { } \mathrm { M } _ { \odot } yr ^ { -1 } .
We discuss the implications of our results in the context of single and binary stellar evolution and propose that M 1-67 represents the best candidate for a post-common envelope scenario in massive stars .