We report observations of a stellar occultation by the classical Kuiper belt object ( 50000 ) Quaoar occurred on 28 June 2019 .
A single-chord high-cadence ( 2 Hz ) photometry dataset was obtained with the Tomo-e Gozen CMOS camera mounted on the 1.05 m Schmidt telescope at Kiso Observatory .
The obtained ingress and egress data do not show any indication of atmospheric refraction and allow to set new 1 \sigma and 3 \sigma upper limits of 6 and 16 nbar , respectively , for the surface pressure of a pure methane atmosphere .
These upper limits are lower than the saturation vapor pressure of methane at Quaoar ’ s expected mean surface temperature ( T \sim 44 K ) and imply the absence of a \sim 10 nbar-level global atmosphere formed by methane ice on Quaoar ’ s surface .