  Wolf-Rayet (WR) 140 is the archetypal periodic dust-forming colliding-wind
binary that hosts a carbon-rich WR (WC) star and an O-star companion with an
orbital period of 7.93 years and an orbital eccentricity of 0.9. Throughout the
past several decades, multiple dust-formation episodes from WR 140 have been
observed that are linked to the binary orbit and occur near the time of
periastron passage. Given its predictable dust-formation episodes, WR 140
presents an ideal astrophysical laboratory for investigating the formation and
evolution of dust in the hostile environment around a massive binary system. In
this paper, we present near- and mid-infrared (IR) spectroscopic and imaging
observations of WR 140 with Subaru/SCExAO+CHARIS, Keck/NIRC2+PyWFS, and
Subaru/COMICS taken between 2020 June and Sept that resolve the circumstellar
dust emission linked to its most recent dust-formation episode in 2016 Dec. Our
spectral energy distribution (SED) analysis of WR 140's resolved circumstellar
dust emission reveals the presence of a hot ($T_\mathrm{d}\sim1000$ K) near-IR
dust component that is co-spatial with the previously known and cooler
($T_\mathrm{d}\sim500$ K) mid-IR dust component composed of $300-500$
{\AA}-sized dust grains. We attribute the hot near-IR dust emission to the
presence of nano-sized ("nanodust") grains and suggest they were formed from
grain-grain collisions or the rotational disruption of the larger grain size
population by radiative torques in the strong radiation field from the central
binary. Lastly, we speculate on the astrophysical implications of nanodust
formation around colliding-wind WC binaries, which may present an early source
of carbonaceous nanodust in the interstellar medium.
