Letter to the Editor

Study of Pluto’s atmosphere based on 2020 stellar occultation light curve results

¹ The International Occultation Timing Association Middle East Section, Iran
e-mail: info@iota-me.com
² Astronomy Department of the Raderon Lab., Burnaby, BC, Canada

Received: 6 July 2021
Accepted: 2 September 2021

Abstract

On 6 June 2020, Pluto’s stellar occultation was successfully observed at a ground-based observatory in Iran, and Pluto’s atmospheric parameters were investigated. We used an atmospheric model of Pluto, assuming a spherical and transparent pure N₂ atmosphere. Using ray-tracing code, the stellar occultation light curve was satisfactorily fit to this model. We found that Pluto’s atmospheric pressure at the reference radius of 1215 km was 6.72 ± 0.48 μbar in June 2020. Our estimated pressure shows a continuation of the pressure increase trend observed since 1988 and does not confirm the rapid pressure decrease tentatively reported in 2019. The pressure evolution is consistent with a seasonal transport model. We conclude that the N₂ sublimation process from Sputnik Planitia is continuing. This study’s result is shown on the diagram of the annual evolution of atmospheric pressure.