New constraint on the atmosphere of (50000) Quaoar from a stellar occultation

Abstract

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.

12 pages, 3 figures, accepted for publication in the Astronomical Journal

References in corpus (3)

• Detection of methane on Kuiper Belt Object (50000) Quaoar
• Amateur telescopes discover a kilometre-sized Kuiper belt object from stellar occultation
• Organized Autotelescopes for Serendipitous Event Survey (OASES): design and performance

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