A meta-analysis of coordinate systems and bibliography of their use on Pluto from Charon’s discovery to the present day

Zangari, A. M.

doi:10.1016/j.icarus.2014.10.040

Cited by 24 publications

(12 citation statements)

References 431 publications

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“…We used individual images as well as basemaps produced from the LORRI and MVIC panchromatic images in this work (Schenk et al, ). New Horizons returned coverage of ≈80% of Charon's surface, but south of ≈30–40°S is in permanent shadow and will not be completely illuminated until 2114 Common Era (Zangari, ). Approximately the same coverage was returned for Pluto.…”

Section: Methodsmentioning

confidence: 99%

Investigation of Charon's Craters With Abrupt Terminus Ejecta, Comparisons With Other Icy Bodies, and Formation Implications

et al. 2018

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On the moon and other airless bodies, ballistically emplaced ejecta transitions from a thinning, continuous inner deposit to become discontinuous beyond approximately one crater radius from the crater rim and can further break into discrete rays and secondary craters. In contrast, on Mars, ejecta often form continuous, distinct, and sometimes thick deposits that transition to a low ridge or escarpment that may be circular or lobate. The Martian ejecta type has been variously termed pancake, rampart, lobate, or layered, and in this work we refer to it as “abrupt termini” ejecta (ATE). Two main formation mechanisms have been proposed, one requiring interaction of the ejecta with the atmosphere and the other mobilization of near‐surface volatiles. ATE morphologies are also unambiguously seen on Ganymede, Europa, Dione, and Tethys, but they are not as common as on Mars. We have identified up to 38 craters on Charon that show signs of ATE, including possible distal ramparts and lobate margins. These ejecta show morphologic and morphometric similarities with other moons in the solar system, which are a subset of the properties observed on Mars. From comparison of these ejecta on Charon and other solar system bodies, we find the strongest support for subsurface volatile mobilization and ejecta fluidization as the main formation mechanism for the ATE, at least on airless, icy worlds. This conclusion comes from the bodies on which they are found, an apparent preference for certain terrains, and the observation that craters with ATE can be near to similarly sized craters that only have gradational ejecta.

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Section: Methodsmentioning

confidence: 99%

Investigation of Charon's Craters With Abrupt Terminus Ejecta, Comparisons With Other Icy Bodies, and Formation Implications

et al. 2018

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“…1 separately for the two observing dates. (Buie et al, 1997;Zangari, 2015), with current summer in the northern hemisphere. Zero longitude on Pluto is the sub-Charon point and the sub-observer point longitude decreases with time.…”

Section: Data Assessmentmentioning

confidence: 99%

Detection of CO and HCN in Pluto’s atmosphere with ALMA

Lellouch

Gurwell

Butler

et al. 2017

Icarus

109

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Observations of the Pluto-Charon system, acquired with the ALMA interferometer on June 12-13, 2015, have led to the detection of the CO(3-2) and HCN(4-3) rotational transitions from Pluto (including the hyperfine structure of HCN), providing a strong confirmation of the presence of CO, and the first observation of HCN in Pluto's atmosphere. The CO and HCN lines probe Pluto's atmosphere up to ∼450 km and ∼900 km altitude, respectively, with a large contribution due to limb emission. The CO detection yields (i) a much improved determination of the CO mole fraction, as 515±40 ppm for a 12 µbar surface pressure (ii) strong constraints on Pluto's mean atmospheric dayside temperature profile over ∼50-400 km, with clear evidence for a well-marked temperature decrease (i.e., mesosphere) above the 30-50 km stratopause and a best-determined temperature of 70±2 K at 300 km, somewhat lower than previously estimated from stellar occultations (81±6 K), and in agreement with recent inferences from New Horizons / Alice solar occultation data. The HCN line shape implies a high abundance of this species in the upper atmosphere, with a mole fraction > 1.5×10 −5 above 450 km and a value of 4×10 −5 near 800 km. Assuming HCN at saturation, this would require a warm (>92 K) upper atmosphere layer; while this is not ruled out by the CO emission, it is inconsistent with the Alicemeasured CH 4 and N 2 line-of-sight column densities. Taken together, the large HCN abundance and the cold upper atmosphere imply supersaturation of HCN to a degree (7-8 orders of magnitude) hitherto unseen in planetary atmospheres, probably due to a lack of condensation nuclei above the haze region and the slow kinetics of condensation at the low pressure and temperature conditions of Pluto's upper atmosphere. HCN is also present in the bottom ∼100 km of the atmosphere, with a 10 −8 -10 −7 mole fraction; this implies either HCN saturation or undersaturation there, depending on the precise stratopause temperature. The HCN column is (1.6±0.4)×10 14 cm −2 , suggesting a surface-referred vertically-integrated net production rate of ∼2×10 7 cm −2 s −1 . Although HCN rotational line cooling affects Pluto's atmosphere heat budget, the amounts determined in this study are insufficient to explain the well-marked mesosphere and upper atmosphere's ∼70 K temperature, which if controlled by HCN cooling would require HCN mole fractions of (3-7)×10 −4 over 400-800 km. We finally report an upper limit on the HC 3 N column density (< 2×10 13 cm −2 ) and on the HC 15 N / HC 14 N ratio (< 1/125).

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“…This section presents the results obtained with the GCM coupled with the haze parametrization. All figures and maps are shown using the new IAU convention, spin north system for definition of the North Pole (Buie et al, 1997;Zangari, 2015), that is with spring-summer in the northern hemisphere during the 21th Century. Here we focus on model predictions in July 2015.…”

Section: Description Of the Reference Simulationsmentioning

confidence: 99%

3D modeling of organic haze in Pluto’s atmosphere

Bertrand

Forget

2017

Icarus

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International audienceThe New Horizons spacecraft, which flew by Pluto on July 14, 2015, revealed the presence of haze in Pluto’s atmosphere that were formed by CH4/N2 photochemistry at high altitudes in Pluto’s atmosphere, as on Titan and Triton. In order to help the analysis of the observations and further investigate the formation of organic haze and its evolution at global scales, we have implemented a simple parametrization of the formation of organic haze in our Pluto General Circulation Model. The production of haze in our model is based on the different steps of aerosol formation as understood on Titan and Triton: photolysis of CH4 in the upper atmosphere by Lyman-α UV radiation, production of various gaseous species, and conversion into solid particles through accumulation and aggregation processes. The simulations use properties of aerosols similar to those observed in the detached haze layer on Titan. We compared two reference simulations ran with a particle radius of 50 nm: with, and without South Pole N2 condensation. We discuss the impact of the particle radius and the lifetime of the precursors on the haze distribution. We simulate CH4 photolysis and the haze formation up to 600 km above the surface. Results show that CH4 photolysis in Pluto’s atmosphere in 2015 occured mostly in the sunlit summer hemisphere with a peak at an altitude of 250 km, though the interplanetary source of Lyman-α flux can induce some photolysis even in the Winter hemisphere. We obtained an extensive haze up to altitudes comparable with the observations, and with non-negligible densities up to 500 km altitude. In both reference simulations, the haze density is not strongly impacted by the meridional circulation. With no South Pole N2 condensation, the maximum nadir opacity and haze extent is obtained at the North Pole. With South Pole N2 condensation, the descending parcel of air above the South Pole leads to a latitudinally more homogeneous haze density with a slight density peak at the South Pole. The visible opacities obtained from the computed mass of haze, which is about 2-4×10−7×10−7 g cm−2−2 in the summer hemisphere, are similar for most of the simulation cases and in the range of 0.001-0.01, which is consistent with recent observations of Pluto and their interpretation

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A meta-analysis of coordinate systems and bibliography of their use on Pluto from Charon’s discovery to the present day

Cited by 24 publications

References 431 publications

Investigation of Charon's Craters With Abrupt Terminus Ejecta, Comparisons With Other Icy Bodies, and Formation Implications

Investigation of Charon's Craters With Abrupt Terminus Ejecta, Comparisons With Other Icy Bodies, and Formation Implications

Detection of CO and HCN in Pluto’s atmosphere with ALMA

3D modeling of organic haze in Pluto’s atmosphere

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