Issue |
A&A
Volume 680, December 2023
|
|
---|---|---|
Article Number | A9 | |
Number of page(s) | 10 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202347477 | |
Published online | 05 December 2023 |
Reconciling results of 2019 and 2020 stellar occultations on Pluto’s atmosphere
New constraints from both the 5 September 2019 event and consistency analysis
1
Purple Mountain Observatory, Chinese Academy of Sciences,
No. 10 Yuanhua Road,
Nanjing
210033, PR China
e-mail: yuanye@pmo.ac.cn
2
School of Astronomy and Space Science, University of Science and Technology of China,
No. 96 Jinzhai Road,
Hefei, Anhui
230026, PR China
3
Hunan Astronomical Association,
Changsha, Hunan
410000, PR China
4
Department of Space Sciences and Astronomy, Hebei Normal University,
No. 20 Road East. 2nd Ring South,
Shijiazhuang, Hebei
050024, PR China
5
Shenzhen Astronomical Observatory,
Tianwen Road,
Shenzhen, Guangdong
518040, PR China
6
Shenzhen Astronomical Society,
22c Seascape Square Taizi Road,
Shenzhen, Guangdong
518040, PR China
7
Shanghai Astronomical Observatory, Chinese Academy of Sciences,
No. 80 Nandan Road,
Shanghai
200030, PR China
8
Nanjing Amateur Astronomers Association,
Nanjing
210000, PR China
Received:
16
July
2023
Accepted:
25
September
2023
A stellar occultation by Pluto on 5 September 2019 yielded positive detections at two separate stations. Using an approach consistent with comparable studies, we derived a surface pressure of 11.478 ± 0.55 µbar for Pluto’s atmosphere from the observations of this event. In addition, to avoid potential method inconsistencies when comparing with historical pressure measurements, we reanalyzed the data for the 15 August 2018 and 17 July 2019 events. All the new measurements provide a bridge between the two different perspectives on the pressure variation since 2015: a rapid pressure drop from previous studies of the 15 August 2018 and 17 July 2019 events and a plateau phase from that of the 6 June 2020 event. The pressure measurement from the 5 September 2019 event aligns with those from 2016, 2018, and 2020, supporting the latter perspective. While the measurements from the 4 June 2011 and 17 July 2019 events suggest probable V-shaped pressure variations that are unaccounted for by the volatile transport model (VTM), the VTM remains applicable on average. Furthermore, the validity of the V-shaped variations is debatable given the stellar faintness of the 4 June 2011 event and the grazing single-chord geometry of the 17 July 2019 event. To reveal and understand all of the significant pressure variations of Pluto’s atmosphere, it is essential to provide constraints on both the short-term and long-term evolution of the interacting atmosphere and surface by continuous pressure monitoring through occultation observations whenever possible, and to complement these with frequent spectroscopy and photometry of the surface.
Key words: Kuiper belt objects: individual: Pluto / planets and satellites: atmospheres / planets and satellites: physical evolution / occultations / techniques: photometric
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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