Detection of a broad 8 $\mu$m UIR feature in the mid-infrared spectrum
  of WR 125 observed with Subaru/COMICS
  We present the detection of a broad 8 $\mu$m feature in newly formed dust
around the carbon-rich Wolf-Rayet (WC) binary WR 125 from N-band low-resolution
(NL; R$\sim$250) spectroscopy between 7.3-13.6 $\mu$m and N-band (11.7 $\mu$m)
and Q-band (18.8 $\mu$m) imaging with Subaru/COMICS in 2019 October. WR 125 is
a colliding wind binary (${\rm WC7+O9}$) that exhibited renewed dust formation
starting in 2018, $\sim$28 years after its first dust formation episode had
been observed. We also compare our infrared photometry with historical
observations and revise the dust-formation period of WR 125 to 28.1 years.
Archival infrared spectra of five dusty WC stars, WR 48a, WR 98a, WR 104, WR
112 and WR 118, obtained with ISO/SWS are reanalyzed and compared with the WR
125 spectrum to search for a similar feature. We analyze the dusty WC spectra
using two different extinction curves to investigate the impact of interstellar
extinction correction on the presence and/or properties of the 8 $\mu$m
feature. All of the dusty WC spectra dereddened with the two different
extinction curves show a broad feature around 8 $\mu$m (FWHM$\sim$1-2 $\mu$m).
We suggest that these 8 $\mu$m features seen in the dusty WC spectra are
related to the Class C unidentified infrared (UIR) features.
