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Pluto's atmospheric structure from the July 2007 stellar occultation


Olkin, CB and Young, LA and French, RG and Young, EF and Buie, MW and Howell, RR and Regester, J and Ruhland, CR and Natusch, T and Ramm, DJ and Giles, AB and Greenhill, JG, Pluto's atmospheric structure from the July 2007 stellar occultation, Icarus, 239 pp. 15-22. ISSN 0019-1035 (2014) [Refereed Article]

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Copyright 2014 Elsevier Inc

DOI: doi:10.1016/j.icarus.2014.05.018


In July 2007, we observed a stellar occultation by Pluto from three sites in New Zealand and Australia. From these occultation observations, we find that Pluto’s atmospheric pressure is still at the increased level measured in 2002 and 2006 with a pressure at a radius of 1275 km of 2.09 ± 0.09 μbar. One of the sites, Mt. John Observatory, was ∼70 km from the shadow center and we recorded the first central-flash occultation by Pluto. We carried out a dual-wavelength observation from this site with two different cameras using filtered high-time resolution observations in the visible from the one-meter telescope at Mt. John Observatory. From our central-flash observations, we find the elliptical shape that best matches the data corresponds to a nearly prolate atmosphere with an ellipticity of 0.09. The flux observed in the central-flash data can be fit equally well with either a haze layer or a thermal gradient in the altitudes probed by the occultation. However, the star light contributing to the central-flash occultation for the haze layer model would pass through a radius of 1130 km from Pluto’s center. Given our current best estimate of Pluto’s surface radius is greater than 1151 km (Tholen, D.J., Buie, M.W. [1997]. Bulk properties of Pluto and Charon. In: Stern, S.A., Tholen, D.J. (Eds.), Pluto and Charon. The University of Arizona Press), we prefer the thermal gradient solution or a combination of haze and thermal gradient to explain the occultation light curves.

DOI for erratum: 10.1016/j.icarus.2016.01.029

Item Details

Item Type:Refereed Article
Keywords:occultations; Pluto, atmosphere; atmosphere, structure
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Giles, AB (Dr Barry Giles)
UTAS Author:Greenhill, JG (Dr John Greenhill)
ID Code:109825
Year Published:2014
Web of Science® Times Cited:15
Deposited By:Mathematics and Physics
Deposited On:2016-07-04
Last Modified:2017-11-03

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