TY - JOUR
T1 - Evidence for a rapid decrease of Pluto's atmospheric pressure revealed by a stellar occultation in 2019
AU - Arimatsu, K.
AU - Hashimoto, G. L.
AU - Kagitani, M.
AU - Sakanoi, T.
AU - Kasaba, Y.
AU - Ohsawa, R.
AU - Urakawa, S.
N1 - Funding Information:
Acknowledgements. We thank Dr. Bruno Sicardy for careful reading and providing constructive suggestions. This research has been partly supported by Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (KAKENHI) Grant Numbers 15J10278, 16K17796, and 18K13606.
Publisher Copyright:
© ESO 2018.
PY - 2020/6/1
Y1 - 2020/6/1
N2 - We report observations of a stellar occultation by Pluto on 2019 July 17. A single-chord high-speed (time resolution = 2 s) photometry dataset was obtained with a CMOS camera mounted on the Tohoku University 60 cm telescope (Haleakala, Hawaii). The occultation light curve is satisfactorily fitted to an existing atmospheric model of Pluto. We find the lowest pressure value at a reference radius of r = 1215 km among those reported after 2012. These reports indicate a possible rapid (approximately 21-5+4% of the previous value) pressure drop between 2016, which is the latest reported estimate, and 2019. However, this drop is detected at a 2.4σ level only and still requires confirmation from future observations. If real, this trend is opposite from the monotonic increase of Pluto's atmospheric pressure reported by previous studies. The observed decrease trend is possibly caused by ongoing N2 condensation processes in the Sputnik Planitia glacier associated with an orbitally driven decline of solar insolation, as predicted by previous theoretical models. However, the observed amplitude of the pressure decrease is larger than the model predictions.
AB - We report observations of a stellar occultation by Pluto on 2019 July 17. A single-chord high-speed (time resolution = 2 s) photometry dataset was obtained with a CMOS camera mounted on the Tohoku University 60 cm telescope (Haleakala, Hawaii). The occultation light curve is satisfactorily fitted to an existing atmospheric model of Pluto. We find the lowest pressure value at a reference radius of r = 1215 km among those reported after 2012. These reports indicate a possible rapid (approximately 21-5+4% of the previous value) pressure drop between 2016, which is the latest reported estimate, and 2019. However, this drop is detected at a 2.4σ level only and still requires confirmation from future observations. If real, this trend is opposite from the monotonic increase of Pluto's atmospheric pressure reported by previous studies. The observed decrease trend is possibly caused by ongoing N2 condensation processes in the Sputnik Planitia glacier associated with an orbitally driven decline of solar insolation, as predicted by previous theoretical models. However, the observed amplitude of the pressure decrease is larger than the model predictions.
KW - Kuiper belt objects: individual: Pluto
KW - Occultations
KW - Planets and satellites: atmospheres
KW - Planets and satellites: physical evolution
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U2 - 10.1051/0004-6361/202037762
DO - 10.1051/0004-6361/202037762
M3 - Article
AN - SCOPUS:85088097976
SN - 0004-6361
VL - 638
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - L5
ER -