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1. Detection of carbon dioxide and hydrogen peroxide on the stratified surface of Charon with JWST

Author

Silvia Protopapa, Ujjwal Raut, Ian Wong, John Stansberry, Geronimo L. Villanueva, Jason Cook, Bryan Holler, William M. Grundy, Rosario Brunetto, Richard J. Cartwright, Bereket Mamo, Joshua P. Emery, Alex H. Parker, Aurelie Guilbert-Lepoutre, Noemi Pinilla-Alonso, Stefanie N. Milam, and Heidi B. Hammel

Subjects
Science
Abstract

Abstract Charon, Pluto’s largest moon, has been extensively studied, with research focusing on its primitive composition and changes due to radiation and photolysis. However, spectral data have so far been limited to wavelengths below 2.5 μm, leaving key aspects unresolved. Here we present the detection of carbon dioxide (CO2) and hydrogen peroxide (H2O2) on the surface of Charon’s northern hemisphere, using JWST data. These detections add to the known chemical inventory that includes crystalline water ice, ammonia-bearing species, and tholin-like darkening constituents previously revealed by ground- and space-based observations. The H2O2 presence indicates active radiolytic/photolytic processing of the water ice-rich surface by solar ultraviolet and interplanetary medium Lyman-α photons, solar wind, and galactic cosmic rays. Through spectral modeling of the surface, we show that the CO2 is present in pure crystalline form and, possibly, in intimately mixed states on the surface. Endogenically sourced subsurface CO2 exposed on the surface is likely the primary source of this component, with possible contributions from irradiation of hydrocarbons mixed with water ice, interfacial radiolysis between carbon deposits and water ice, and the implantation of energetic carbon ions from the solar wind and solar energetic particles.

Published
2024
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2. Prominent Mid-infrared Excess of the Dwarf Planet (136472) Makemake Discovered by JWST/MIRI Indicates Ongoing Activity

Author

Csaba Kiss, Thomas G. Müller, Anikó Farkas-Takács, Attila Moór, Silvia Protopapa, Alex H. Parker, Pablo Santos-Sanz, Jose Luis Ortiz, Bryan J. Holler, Ian Wong, John Stansberry, Estela Fernández-Valenzuela, Christopher R. Glein, Emmanuel Lellouch, Esa Vilenius, Csilla E. Kalup, Zsolt Regály, Róbert Szakáts, Gábor Marton, András Pál, and Gyula M. Szabó

Subjects
Trans-Neptunian objects, Classical Kuiper belt objects, Planetary rings, Asteroid surfaces, Planetary thermal histories, Astrophysics, QB460-466
Abstract

We report on the discovery of a very prominent mid-infrared (18–25 μ m) excess associated with the trans-Neptunian dwarf planet (136472) Makemake. The excess, detected by the Mid-Infrared Instrument of the James Webb Space Telescope, along with previous measurements from the Spitzer and Herschel space telescopes, indicates the occurrence of temperatures of ∼150 K, much higher than what solid surfaces at Makemake’s heliocentric distance could reach by solar irradiation. We identify two potential explanations: a continuously visible, currently active region powered by subsurface upwelling and possibly cryovolcanic activity covering ≤1% of Makemake’s surface or an as-yet-undetected ring containing very small carbonaceous dust grains, which have not been seen before in trans-Neptunian or Centaur rings. Both scenarios point to unprecedented phenomena among trans-Neptunian objects and could greatly impact our understanding of these distant worlds.

Published
2024
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3. JWST Reveals CO Ice, Concentrated CO2 Deposits, and Evidence for Carbonates Potentially Sourced from Ariel’s Interior

Author

Richard J. Cartwright, Bryan J. Holler, William M. Grundy, Stephen C. Tegler, Marc Neveu, Ujjwal Raut, Christopher R. Glein, Tom A. Nordheim, Joshua P. Emery, Julie C. Castillo-Rogez, Eric Quirico, Silvia Protopapa, Chloe B. Beddingfield, Matthew M. Hedman, Katherine de Kleer, Riley A. DeColibus, Anastasia N. Morgan, Ryan Wochner, Kevin P. Hand, Geronimo L. Villanueva, Sara Faggi, Noemi Pinilla-Alonso, David E. Trilling, and Michael M. Mueller

Subjects
Carbon dioxide, Ice spectroscopy, Surface ices, Surface processes, Surface composition, James Webb Space Telescope, Astrophysics, QB460-466
Abstract

The Uranian moon Ariel exhibits a diversity of geologically young landforms, with a surface composition rich in CO _2 ice. The origin of CO _2 and other species, however, remains uncertain. We report observations of Ariel’s leading and trailing hemispheres, collected with NIRSpec (2.87–5.10 μ m) on the James Webb Space Telescope. These data shed new light on Ariel's spectral properties, revealing a double-lobed CO _2 ice scattering peak centered near 4.20 and 4.25 μ m, with the 4.25 μ m lobe possibly representing the largest CO _2 Fresnel peak yet observed in the solar system. A prominent 4.38 μ m ^13 CO _2 ice feature is also present, as is a 4.90 μ m band that results from ^12 CO _2 ice. The spectra reveal a 4.67 μ m ^12 CO ice band and a broad 4.02 μ m band that might result from carbonate minerals. The data confirm that features associated with CO _2 and CO are notably stronger on Ariel’s trailing hemisphere compared to its leading hemisphere. We compared the detected CO _2 features to synthetic spectra of CO _2 ice and mixtures of CO _2 with CO, H _2 O, and amorphous carbon, finding that CO _2 could be concentrated in deposits thicker than ∼10 mm on Ariel’s trailing hemisphere. Comparison to laboratory data indicates that CO is likely mixed with CO _2 . The evidence for thick CO _2 ice deposits and the possible presence of carbonates on both hemispheres suggests that some carbon oxides could be sourced from Ariel’s interior, with their surface distributions modified by charged particle bombardment, sublimation, and seasonal migration of CO and CO _2 from high to low latitudes.

Published
2024
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4. Revealing Callisto’s Carbon-rich Surface and CO2 Atmosphere with JWST

Author

Richard J. Cartwright, Geronimo L. Villanueva, Bryan J. Holler, Maria Camarca, Sara Faggi, Marc Neveu, Lorenz Roth, Ujjwal Raut, Christopher R. Glein, Julie C. Castillo-Rogez, Michael J. Malaska, Dominique Bockelée-Morvan, Tom A. Nordheim, Kevin P. Hand, Giovanni Strazzulla, Yvonne J. Pendleton, Katherine de Kleer, Chloe B. Beddingfield, Imke de Pater, Dale P. Cruikshank, and Silvia Protopapa

Subjects
Infrared spectroscopy, Galilean satellites, Callisto, James Webb Space Telescope, Natural satellite atmospheres, Natural satellite surfaces, Astronomy, QB1-991
Abstract

We analyzed spectral cubes of Callisto’s leading and trailing hemispheres, collected with the NIRSpec Integrated Field Unit (G395H) on the James Webb Space Telescope. These spatially resolved data show strong 4.25 μ m absorption bands resulting from solid-state ^12 CO _2 , with the strongest spectral features at low latitudes near the center of its trailing hemisphere, consistent with radiolytic production spurred by magnetospheric plasma interacting with native H _2 O mixed with carbonaceous compounds. We detected CO _2 rovibrational emission lines between 4.2 and 4.3 μ m over both hemispheres, confirming the global presence of CO _2 gas in Callisto’s tenuous atmosphere. These results represent the first detection of CO _2 gas over Callisto’s trailing side. The distribution of CO _2 gas is offset from the subsolar region on either hemisphere, suggesting that sputtering, radiolysis, and geologic processes help sustain Callisto’s atmosphere. We detected a 4.38 μ m absorption band that likely results from solid-state ^13 CO _2 . A prominent 4.57 μ m absorption band that might result from CN-bearing organics is present and significantly stronger on Callisto’s leading hemisphere, unlike ^12 CO _2 , suggesting these two spectral features are spatially antiassociated. The distribution of the 4.57 μ m band is more consistent with a native origin and/or accumulation of dust from Jupiter’s irregular satellites. Other, more subtle absorption features could result from CH-bearing organics, CO, carbonyl sulfide, and Na-bearing minerals. These results highlight the need for preparatory laboratory work and improved surface–atmosphere interaction models to better understand carbon chemistry on the icy Galilean moons before the arrival of NASA’s Europa Clipper and ESA’s JUICE spacecraft.

Published
2024
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5. Large-scale cryovolcanic resurfacing on Pluto

Author

Kelsi N. Singer, Oliver L. White, Bernard Schmitt, Erika L. Rader, Silvia Protopapa, William M. Grundy, Dale P. Cruikshank, Tanguy Bertrand, Paul M. Schenk, William B. McKinnon, S. Alan Stern, Rajani D. Dhingra, Kirby D. Runyon, Ross A. Beyer, Veronica J. Bray, Cristina Dalle Ore, John R. Spencer, Jeffrey M. Moore, Francis Nimmo, James T. Keane, Leslie A. Young, Catherine B. Olkin, Tod R. Lauer, Harold A. Weaver, and Kimberly Ennico-Smith

Subjects
Science
Abstract

Giant icy volcanos (cryovolcanos) on Pluto are unique in the imaged solar system and provide evidence for unexpected, active geology late in Pluto’s history.

Published
2022
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6. The LCO Outbursting Objects Key Project: Overview and Year 1 Status

Author

Tim Lister, Michael S. P. Kelley, Carrie E. Holt, Henry H. Hsieh, Michele T. Bannister, Aayushi A. Verma, Matthew M. Dobson, Matthew M. Knight, Youssef Moulane, Megan E. Schwamb, Dennis Bodewits, James Bauer, Joseph Chatelain, Estela Fernández-Valenzuela, Daniel Gardener, Geza Gyuk, Mark Hammergren, Ky Huynh, Emmanuel Jehin, Rosita Kokotanekova, Eva Lilly, Man-To Hui, Adam McKay, Cyrielle Opitom, Silvia Protopapa, Ryan Ridden-Harper, Charles Schambeau, Colin Snodgrass, Cai Stoddard-Jones, Helen Usher, Kacper Wierzchos, Padma A. Yanamandra-Fisher, Quanzhi 泉志 Ye 叶, Edward Gomez, and Sarah Greenstreet

Published
2022
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7. Testing Short-term Variability and Sampling of Primary Volatiles in Comet 46P/Wirtanen

Author

Younas Khan, Erika L. Gibb, Boncho P. Bonev, Nathan X. Roth, Mohammad Saki, Michael A Disanti, Neil Dello Russo, Ronald J. Vervack, Jr, Adam J McKay, Michael R Combi, Yinsi Shou, Martin A. Cordiner, Hideyo Kawakita, Nicolas Fougere, and Silvia Protopapa

Subjects
Lunar And Planetary Science And Exploration
Abstract

The exceptionally favorable close approach of Jupiter-family comet 46P/Wirtanen in 2018 December enabled characterization of its primary volatile composition with exceptionally high spatial resolution and sensitivities using the iSHELL spectrograph at the NASA Infrared Telescope Facility on Maunakea, HI. We sampled emissions from H2O, HCN, C2H2, NH3,C2H6, and CH3OH on UT 2018 December 21 using two instrumental settings that spanned the 2.9–3.6μm spectral region. We also obtained a sensitive 3σupper limit for H2CO and for the rarely studied molecule HC3N. We report rotational temperatures, production rates, and mixing ratios(relative to H2O as well as to C2H6). We place our results in context by comparing them with other comets observed at near-IR wavelengths. We also compare our results with those obtained using the NIRSPEC-2 spectrograph on Keck II on UT December 17 and 18 and with results obtained from iSHELL on other dates during the same apparition. Within1–2σ uncertainty, production rates obtained for all molecules in this work were consistent with those obtained using NIRSPEC-2 except H2O, indicating low-level variability on a timescale of days. Mixing ratios with respect to H2O in 46P/Wirtanen were consistent with corresponding values from NIRSPEC-2 within the uncertainty with the exception of CH3OH, which yielded a higher ratio on December 21. Our measurements afforded a high temporal resolution that spanned∼2/3 of the rotational period of 46P/Wirtanen, enabling us to test short-term variability in the production rates of H2O and HCN due to rotational effects. Both H2O and HCN production rates showed similar temporal variability, resulting in nearly constant HCN/H2O

Published
2021
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8. Disk-resolved Photometric Properties of Pluto and the Coloring Materials across its Surface

Author

Silvia Protopapa, Cathy B. Olkin, Will M. Grundy, Jian-Yang Li, Anne Verbiscer, Dale P. Cruikshank, Thomas Gautier, Eric Quirico, Jason C. Cook, Dennis Reuter, Carly J. A. Howett, Alan Stern, Ross A. Beyer, Simon Porter, Leslie A. Young, Harold A. Weaver, Kimberly Ennico, Cristina M. Dalle Ore, Francesca Scipioni, and Kelsi N. Singer

Subjects
Astronomy, Astrophysics
Abstract

A multiwavelength regionally dependent photometric analysis of Pluto's anti-Charon-facing hemisphere using images collected by New Horizons' Multispectral Visible Imaging Camera (MVIC) reveals large variations in the absolute value and spectral slope of the single-scattering albedo. Four regions of interest are analyzed: the dark equatorial belt, Pluto's north pole, nitrogen-rich regions, and the mid-latitude terrains. Regions dominated by volatile ices such as Lowell Regio and Sputnik Planitia present single-scattering albedos of ~0.98 at 492 nm, almost neutral across MVIC's visible wavelength range (400–910 nm), indicating limited contributions from tholin materials. Pluto's dark equatorial regions, informally named Cthulhu and Krun Maculae, have single-scattering albedos of ~0.16 at 492 nm and are the reddest regions. Applying the Hapke radiative transfer model to combined MVIC and Linear Etalon Imaging Spectral Array (LEISA) spectra (400–2500 nm) of Cthulhu Macula and Lowell Regio successfully reproduces the spectral properties of these two regions of dramatically disparate coloration, composition, and morphology. Since this model uses only a single coloring agent, very similar to the Titan-like tholin of Khare et al., to account for all of Pluto's colors, this result supports the Grundy et al. conclusion that Pluto's coloration is the result of photochemical products mostly produced in the atmosphere. Although cosmic rays and extreme ultraviolet photons reach Pluto's surface where they can drive chemical processing, observations of diverse surface colors do not require different chemical products produced in different environments. We report a correction scaling factor in the LEISA radiometric calibration of 0.74 ± 0.05.

Published
2020
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9. Charon’s refractory factory

Author

Ujjwal Raut, Benjamin D. Teolis, Joshua A. Kammer, Caleb J. Gimar, Joshua S. Brody, G. Randall Gladstone, Carly J. A. Howett, Silvia Protopapa, and Kurt D. Retherford

Subjects
Multidisciplinary
Abstract

We combine novel laboratory experiments and exospheric modeling to reveal that “dynamic” Ly-α photolysis of Plutonian methane generates a photolytic refractory distribution on Charon that increases with latitude, consistent with poleward darkening observed in the New Horizons images. The flux ratio of the condensing methane to the interplanetary medium Ly-α photons, φ, controls the distribution and composition of Charon’s photoproducts. Mid-latitude regions are likely to host complex refractories emerging from low-φ photolysis, while high-φ photolysis at the polar zones primarily generate ethane. However, ethane being colorless does not contribute to the reddish polar hue. Solar wind radiolysis of Ly-α–cooked polar frost past spring sunrise may synthesize increasingly complex, redder refractories responsible for the unique albedo on this enigmatic moon.

Published
2023

12. Persephone: A Pluto-system Orbiter and Kuiper Belt Explorer

Author

Carly J. A. Howett, Stuart J. Robbins, Bryan J. Holler, Amanda Hendrix, Karl B. Fielhauer, Mark E. Perry, Fazle E. Siddique, Clint T. Apland, James C. Leary, S. Alan Stern, Heather Elliott, Francis Nimmo, Simon B. Porter, Silvia Protopapa, Kelsi N. Singer, Orenthal J. Tucker, Anne J. Verbiscer, Bruce B. Andrews, Stewart S. Bushman, Adam V. Crifasi, Doug Crowley, Clint L. Edwards, Carolyn M. Ernst, Blair D. Fonville, David P. Frankford, Dan T. Gallagher, Mark E. Holdridge, Jack W. Hunt, J. J. Kavelaars, Chris J. Krupiarz, James S. Kuhn, William McKinnon, Hari Nair, David H. Napolillo, Jon P. Pineau, Jani Radebaugh, Rachel O. Sholder, John R. Spencer, Adam Thodey, Samantha R. Walters, Bruce D. Williams, Robert J. Wilson, and Leslie A. Young

Published
2021
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13. The Geophysical Environment of (486958) Arrokoth—A Small Kuiper Belt Object Explored by New Horizons

Author

James T. Keane, Simon B. Porter, Ross A. Beyer, Orkan M. Umurhan, William B. McKinnon, Jeffrey M. Moore, John R. Spencer, S. Alan Stern, Carver J. Bierson, Richard P. Binzel, Douglas P. Hamilton, Carey M. Lisse, Xiaochen Mao, Silvia Protopapa, Paul M. Schenk, Mark R. Showalter, John A. Stansberry, Oliver L. White, Anne J. Verbiscer, Joel W. Parker, Catherine B. Olkin, Harold A. Weaver, and Kelsi N. Singer

Subjects
Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous)
Published
2022

14. Pluto's Sputnik Planitia: Composition of geological units from infrared spectroscopy

Author

J. M. Moore, R. P. Binzel, Kelsi N. Singer, Harold A. Weaver, Bernard Schmitt, Francesca Scipioni, A. J. Verbiscer, Catherine B. Olkin, Tanguy Bertrand, Silvia Protopapa, D. C. Reuter, C. M. Dalle Ore, C. Beddingfield-Cartwright, Oliver L. White, D. E. Jennings, J. R. Spencer, Dale P. Cruikshank, Jason C. Cook, Leslie A. Young, William M. Grundy, S. A. Stern, Search for Extraterrestrial Intelligence Institute (SETI), NASA Ames Research Center (ARC), Pinhead Institute, Lowell Observatory [Flagstaff], Massachusetts Institute of Technology (MIT), NASA Goddard Space Flight Center (GSFC), Southwest Research Institute [Boulder] (SwRI), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), University of Virginia [Charlottesville], and CNES, système Solaire

Subjects
Endmember, 010504 meteorology & atmospheric sciences, Pluto, Near-infrared spectroscopy, Elevation, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, surface composition, Astronomy and Astrophysics, Tholin, 15. Life on land, geological units, Spatial distribution, 01 natural sciences, Spectral line, ices, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Spectral slope, infrared spectroscopy, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

International audience; We have compared spectroscopic data of Sputnik Planitia on Pluto, as acquired by New Horizons’ Linear Etalon Imaging Spectral Array (LEISA) instrument, to the geomorphology as mapped by White et al. (2017) using visible and panchromatic imaging acquired by the LOng-Range Reconnaissance Imager (LORRI) and the Multi-spectral Visible Imaging Camera (MVIC). We have focused on 13 of the geologic units identified by White et al. (2017), which include the plains and mountain units contained within the Sputnik basin. We divided the map of Sputnik Planitia into 15 provinces, each containing one or more geologic units, and we use LEISA to calculate the average spectra of the units inside the 15 provinces. Hapke-based modeling was then applied to the average spectra of the units to infer their surface composition, and to determine if the composition resulting from the modeling of LEISA spectra reflects the geomorphologic analyses of LORRI data, and if areas classified as being the same geologically, but which are geographically separated, share a similar composition. We investigated the spatial distribution of the most abundant ices on Pluto’s surface - CH4, N2, CO, H2O, and a non-ice component presumed to be a macromolecular carbon-rich material, termed a tholin, that imparts a positive spectral slope in the visible spectral region and a negative spectral slope longward of ~1.1 μm. Because the exact nature of the non-ice component is still debated and because the negative spectral slope of the available tholins in the near infrared does not perfectly match the Pluto data, for spectral modeling purposes we reference it generically as the negative spectral slope endmember (NSS endmember). We created maps of variations in the integrated band depth (from LEISA data) and areal mass fraction (from the modeling) of the components. The analysis of correlations between the occurrences of the endmembers in the geologic units led to the observation of an anomalous suppression of the strong CH4 absorption bands in units with compositions that are dominated by H2O ice and the NSS endmember. Exploring the mutual variation of the CH4 and N2 integrated band depths with the abundance of crystalline H2O and NSS endmember revealed that the NSS endmember is primarily responsible for the suppression of CH4 absorptions in mountainous units located along the western edge of Sputnik Planitia. Our spectroscopic analyses have provided additional insight into the geological processes that have shaped Sputnik Planitia. A general increase in volatile abundance from the north to the south of Sputnik Planitia is observed. Such an increase first observed and interpreted by Protopapa et al., 2017 and later confirmed by climate modeling (Bertrand et al., 2018) is expressed geomorphologically in the form of preferential deposition of N2 ice in the upland and mountainous regions bordering the plains of southern Sputnik Planitia. Relatively high amounts of pure CH4 are seen at the southern Tenzing Montes, which are a natural site for CH4 deposition owing to their great elevation and the lower insolation they are presently receiving. The NSS endmember correlates the existence of tholins within certain units, mostly those coating the low-latitude mountain ranges that are co-latitudinal with the tholin-covered Cthulhu Macula. The spectral analysis has also revealed compositional differences between the handful of occurrences of northern non-cellular plains and the surrounding cellular plains, all of which are located within the portion of Sputnik Planitia that is presently experiencing net sublimation of volatiles, and which do not therefore exhibit a surface layer of bright, freshly-deposited N2 ice. The compositional differences between the cellular and non-cellular plains here hint at the effectiveness of convection in entraining and trapping tholins within the body of the cellular plains, while preventing the spread of such tholins to abutting non-cellular plains.

Published
2021

15. Minor Body Science with the Nancy Grace Roman Space Telescope

Author

Andrea Longobardo, Henry H. Hsieh, Robert A. West, Nader Haghighipour, Michael S. P. Kelley, Tony L. Farnham, Conor A. Nixon, Andrew S. Rivkin, Bryan J. Holler, Cristina A. Thomas, David Trilling, Amanda A. Sickafoose, Lynnae C. Quick, Michele T. Bannister, Dennis Bodewits, Matthew M. Knight, Jeffrey W. Kruk, Alan W. Harris, Charles Alcock, Stefanie N. Milam, Ernesto Palomba, E. A. Kramer, Jason Rhodes, Gordon L. Bjoraker, Amanda S. Bosh, Marc W. Buie, Christopher M. Hirata, Silvia Protopapa, James Bauer, Paul S. Hardersen, Darin Ragozzine, and G. Sarid

Subjects
Spitzer Space Telescope, media_common.quotation_subject, Astronomy, Art, Minor (academic), media_common
Published
2021

16. Critical Laboratory Studies to Advance Planetary Science and Support Missions

Author

Murthy S. Gudipati, Morgan L. Cable, Jürgen Blum, Silvia Protopapa, Aaron Noell, Stefanie N. Milam, Michel Nuevo, Baptiste Journaux, Edith C. Fayolle, Jennifer Hanley, Laurie Barge, Rachel L. Smith, Jessica M. Weber, Farid Salama, Sarah E. Waller, Mohit Melwani Daswani, Jason P. Dworkin, Bryana L. Henderson, Chris J. Bennett, Ella Sciamma-O'Brien, and Brian J. Drouin

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Engineering, Planetary science, business.industry, FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, business, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Earth and Planetary Astrophysics, Astrobiology
Abstract

Laboratory studies for planetary science and astrobiology aimat advancing our understanding of the Solar System through the promotion of theoretical and experimental research into the underlying processes that shape it. Laboratory studies (experimental and theoretical) are crucial to interpret observations and mission data, and are key incubators for new mission concepts as well as instrument development and calibration. They also play a vital role in determining habitability of Solar System bodies, enhancing our understanding of the origin of life, and in the search for signs of life beyond Earth, all critical elements of astrobiology. Here we present an overview of the planetary science areas where laboratory studies are critically needed, in particular in the next decade. These areas include planetary & satellites atmospheres, surfaces, and interiors, primitive bodies such as asteroids, meteorites, comets, and trans-Neptunian objects, and signs of life. Generating targeted experimental and theoretical laboratory data that are relevant for a better understanding of the physical, chemical, and biological processes occurring in these environments is crucial. For each area we present i) a brief overview of the state-of-the-art laboratory work, ii) the challenges to analyze and interpret data sets from missions and ground-based observations and to support mission and concept development, and iii) recommendations for high priority laboratory studies., White paper submitted to the Planetary Science Decadal Survey 2013-2022

Published
2021

17. Testing tholins as analogues of the dark reddish material covering Pluto’s Cthulhu region

Author

Bernard Schmitt, Silvia Protopapa, Dale P. Cruikshank, Alan Stern, Olivier Poch, Véronique Vuitton, C. M. Dalle Ore, Tanguy Bertrand, Lora Jovanovic, Leslie A. Young, Marie Fayolle, Thomas Gautier, Nathalie Carrasco, Eric Quirico, Will Grundy, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Delft University of Technology (TU Delft), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lowell Observatory [Flagstaff], Southwest Research Institute [Boulder] (SwRI), NASA Ames Research Center (ARC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Institut de biologie et chimie des protéines [Lyon] (IBCP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Lipides - Nutrition - Cancer (U866) (LNC), Université de Bourgogne (UB)-Institut National de la Santé et de la Recherche Médicale (INSERM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'Alimentation de Dijon (ENSBANA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris)

Subjects
Materials science, 010504 meteorology & atmospheric sciences, Pluto's Cthulhu region, Continuum (design consultancy), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Pluto’s Cthulhu region, Astrophysics, 01 natural sciences, Tholins, Atmosphere, New Horizons, symbols.namesake, 0103 physical sciences, Radiative transfer, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Single-scattering albedo, Astronomy and Astrophysics, Tholin, Pluto, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, symbols, Titan (rocket family)
Abstract

International audience; New Horizons' reectance spectra of the Cthulhu dark belt of Pluto were modelled with tholins. Reectance factors, phase function and optical constants of these tholins were numerically determined from tholins' reectance measurements. Tholins do not reproduce the featureless spectra of Cthulhu. These results could suggest that this region is covered with a highly porous layer of organic aerosolsPluto’s fly-by by the New Horizons spacecraft in July 2015 has revealed a dark reddish equatorial region, named Cthulhu, covered by a dark, non-icy material whose origin and composition have yet to be determined. It has been suggested that this material could form from the sedimentation of photochemical aerosols, originating from dissociation and ionisation processes in Pluto’s high atmosphere (similarly to aerosols forming Titan’s haze). This hypothesis is here further investigated by comparing New Horizons spectra collected both in the visible and the near-infrared to laboratory reflectance measurements of analogues of Pluto’s aerosols (Pluto tholins). These aerosols were synthesised in conditions mimicking Pluto’s atmosphere, and their optical and reflectance properties were determined, before being used in Hapke models. In particular, the single scattering albedo and phase function of Pluto tholins were retrieved through Hapke model inversion, performed from laboratory reflectance spectra collected under various geometries. From reconstructed reflectance spectra and direct comparison with New Horizons data, some of these tholins are shown to reproduce the photometric level (i.e. reflectance continuum) reasonably well in the near-infrared. Nevertheless, a misfit of the red visible slope still remains and tholins absorption bands present in the modelled spectra are absent in those collected by the New Horizons instruments. Several hypotheses are considered to explain the absence of these absorption features in LEISA data, namely high porosity effects or GCR irradiation. The formation of highly porous structures, which is currently our preferred scenario, could be promoted by either sublimation of ices initially mixed with the aerosols, or gentle deposition under Pluto’s weak gravity.

Published
2021
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18. Optical constants of Pluto aerosol analogues from UV to near-IR

Author

Nathalie Carrasco, L. Johann, Marie Fayolle, Tanguy Bertrand, Laurent Broch, Thomas Gautier, Pascal Rannou, Eric Quirico, Aotmane En Naciri, Silvia Protopapa, Lora Jovanovic, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Southwest Research Institute [Boulder] (SwRI), NASA Ames Research Center (ARC), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Delft University of Technology (TU Delft), European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)

Subjects
Materials science, 010504 meteorology & atmospheric sciences, 01 natural sciences, Astrobiology, Atmosphere, symbols.namesake, 0103 physical sciences, Mixing ratio, Radiative transfer, Optical constants, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Pluto, Astronomy and Astrophysics, Tholin, Aerosol, haze, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], atmosphere, symbols, Titan (rocket family), aerosols
Abstract

International audience; Photochemical aerosols were detected as high as 350 km of altitude in Pluto's atmosphere during the New Horizons fly-by. These aerosols are thought to affect Pluto's climate, by acting as cooling agents, and the colours of Pluto's surface, in particular in the dark regions named Cthulhu and Krun and at the North Pole. Pluto atmospheric and surface models have so far used the optical constants of Titan aerosol analogues (tholins), whereas their chemical composition is known to differ from that of Pluto aerosol analogues.In order to provide a new set of optical constants for Pluto tholins, we synthesized analogues of Pluto's aerosols and determined with spectroscopic ellipsometry their optical constants from 270 to 2100 nm. Three types of samples were produced from N2:CH4:CO gas mixtures differing in their CH4:N2 mixing ratio, representative of different altitudes in Pluto's current atmosphere or different seasons or epochs of Pluto.Our analysis shows a strong absorption by Pluto tholins in the UV and visible spectral ranges, with k index of a few 10−1 at 270 nm, in agreement with N- and O-bearing organic molecules. Pluto tholins are less absorbent in the near-IR than in the UV–Vis wavelength range, with k of a few 10−3 between 600 and 2100 nm. Our comparative study highlights the dependency of n and k indices to the CH4:N2 mixing ratio. Aerosols formed at different altitudes in Pluto's atmosphere or during different seasons or epochs of Pluto will therefore affect the budget of Pluto radiative transfer differently.The optical constants presented in this study were tested with a Pluto surface model and with a model of light scattering. The surface modelling results highlight the suitability of these optical constants to reproduce Pluto compositional observations in the visible spectral range by MVIC and LEISA. The atmospheric modelling results conclude that Pluto tholins absorb 5 to 10 times less than Titan tholins at 500 nm, and this lower absorption is consistent with Alice observations of Pluto's haze.

Published
2021
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19. A Near-surface Temperature Model of Arrokoth

Author

Orkan M. Umurhan, William M. Grundy, Michael K. Bird, Ross Beyer, James T. Keane, Ivan R. Linscott, Samuel Birch, Carver Bierson, Leslie A. Young, S. Alan Stern, Carey M. Lisse, Carly J. A. Howett, Silvia Protopapa, John R. Spencer, Richard P. Binzel, William B. McKinnon, Tod R. Lauer, Harold A. Weaver, Catherine B. Olkin, Kelsi N. Singer, Anne J. Verbiscer, and Alex H. Parker

Subjects
Geophysics, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Astronomy and Astrophysics
Abstract

A near-surface thermal model for Arrokoth is developed based on the recently released 105 facet model of the body. This thermal solution takes into account Arrokoth’s surface reradiation back onto itself. The solution method exploits Arrokoth’s periodic orbital character to develop a thermal response using a time-asymptotic solution method, which involves a Fourier transform solution of the heat equation, an approach recently used by others. We display detailed thermal solutions assuming that Arrokoth’s near-surface material’s thermal inertia  = 2.5 W/m−2 K−1 s1/2. We predict that at New Horizons’ encounter with Arrokoth, its encounter hemisphere surface temperatures were ∼57–59 K in its polar regions, 30–40 K in its equatorial zones, and 11–13 K for its winter hemisphere. Arrokoth’s orbitally averaged temperatures are around 30–35 K in its polar regions and closer to 40 K near its equatorial zones. Thermal reradiation from the surrounding surface amounts to less than 5% of the total energy budget, while the total energy ensconced into and exhumed out of Arrokoth’s interior via thermal conduction over one orbit is about 0.5% of the total energy budget. As a generalized application of this thermal modeling together with other Kuiper Belt object origins considerations, we favor the interpretation that New Horizons’ REX instrument’s 29 ± 5 K brightness temperature measurement is consistent with Arrokoth’s near-surface material being made of sub-to-few-millimeter-size tholin-coated amorphous H2O ice grains with 1 W/m−2 K−1 s1/2 <  < 10–20 W/m−2 K−1 s1/2 and which are characterized by an X-band emissivity in the range 0.9 and 1.

Published
2022

20. The Diverse Shapes of Dwarf Planet and Large KBO Phase Curves Observed from New Horizons

Author

Anne J. Verbiscer, Paul Helfenstein, Simon B. Porter, Susan D. Benecchi, J. J. Kavelaars, Tod R. Lauer, Jinghan Peng, Silvia Protopapa, John R. Spencer, S. Alan Stern, Harold A. Weaver, Marc W. Buie, Bonnie J. Buratti, Catherine B. Olkin, Joel Parker, Kelsi N. Singer, and Leslie A. Young

Subjects
Geophysics, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Astronomy and Astrophysics
Abstract

Observing dwarf planets and other large Kuiper Belt objects (KBOs) from vantage points between 8 and 47 au from the Sun, NASA’s New Horizons spacecraft has found diversity in the shapes of their solar phase curves. Here we extend solar phase angle coverage of dwarf planets (136199) Eris, (136472) Makemake, and (136108) Haumea; large KBOs (28978) Ixion, (50000) Quaoar, (307261) 2002 MS4, and (556416) 2014 OE394; and Neptune’s satellite Triton to phase angles as high as α = 94° using New Horizons data and fit the resulting solar phase curves to the Hapke photometric model. When accounting for sparse α sampling, these fits yield large uncertainties in the Hapke parameters; however, opposition effect parameters are generally well constrained and suggest a significant range of regolith maturation ages among these bodies. The expanded range in α enables evaluation of Bond albedos, phase integrals, rotation curves at high α, and comparisons of the surface scattering properties of these objects with those of others in the solar system. The dwarf planets with surface compositions dominated by hypervolatiles, Eris and Makemake, and Triton (a likely former KBO) have shallower solar phase curve slopes (i.e., lower phase coefficients, higher phase integrals, and Bond albedos) than objects with volatile-poor surfaces. The total amplitude of Haumea’s rotation curve at α = 48° is Δm = 0.6 ± 0.2 mag, nearly twice that of its rotation curve measured from Earth at low phase angles. Bond albedos range from 0.037 ± 0.007 for Ixion to 0.99 − 0.09 + 0.01 for Eris.

Published
2022

21. Modeling Pluto's Minimum Pressure: Implications for Haze Production

Author

Oliver L. White, Bernard Schmitt, Perianne E. Johnson, Kathy E. Mandt, Briley Lewis, Leslie A. Young, John Stansberry, Silvia Protopapa, L. Gabasova, University of Colorado [Colorado Springs] (UCCS), Southwest Research Institute [Boulder] (SwRI), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), University of California, Space Telescope Science Institute (STSci), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), NASA Ames Research Center (ARC), and Search for Extraterrestrial Intelligence Institute (SETI)

Subjects
Haze, Materials science, 010504 meteorology & atmospheric sciences, Ices, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Surface pressure, Atmospheric sciences, 01 natural sciences, Physics - Geophysics, 0103 physical sciences, Mixing ratio, surface, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Pluto, Atmospheric pressure, Drop (liquid), Northern Hemisphere, Astronomy and Astrophysics, Geophysics (physics.geo-ph), haze, 13. Climate action, Space and Planetary Science, atmosphere, Astrophysics - Earth and Planetary Astrophysics
Abstract

Pluto has a heterogeneous surface, despite a global haze deposition rate of ~1 micrometer per orbit (Cheng et al., 2017; Grundy et al., 2018). While there could be spatial variation in the deposition rate, this has not yet been rigorously quantified, and naively the haze should coat the surface more uniformly than was observed. One way (among many) to explain this contradiction is for atmospheric pressure at the surface to drop low enough to interrupt haze production and stop the deposition of particles onto part of the surface, driving heterogeneity. If the surface pressure drops to less than 10^-3 - 10^-4 microbar and the CH4 mixing ratio remains nearly constant at the observed 2015 value, the atmosphere becomes transparent to ultraviolet radiation (Young et al., 2018), which would shut off haze production at its source. If the surface pressure falls below 0.06 microbar, the atmosphere ceases to be global, and instead is localized over only the warmest part of the surface, restricting the location of deposition (Spencer et al., 1997). In Pluto's current atmosphere, haze monomers collect together into aggregate particles at beginning at 0.5 microbar; if the surface pressure falls below this limit, the appearance of particles deposited at different times of year and in different locations could be different. We use VT3D, an energy balance model (Young, 2017), to model the surface pressure on Pluto in current and past orbital configurations for four possible static N2 ice distributions: the observed northern hemisphere distribution with (1) a bare southern hemisphere, (2) a south polar cap, (3) a southern zonal band, and finally (4) a distribution that is bare everywhere except inside the boundary of Sputnik Planitia. We also present a sensitivity study showing the effect of mobile N2 ice...(cont.), accepted for publication in Icarus

Published
2020

22. The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth

Author

Harold A. Weaver, J. Wm. Parker, Paolo Tanga, Stuart J. Robbins, Harold J. Reitsema, Carver J. Bierson, Dennis C. Reuter, Matthew E. Hill, Dale P. Cruikshank, Stephen Gwyn, Mark R. Showalter, Alex Parker, B. H. May, William M. Grundy, Oliver L. White, Douglas P. Hamilton, Orkan M. Umurhan, M. Mountain, Jj Kavelaars, Kelsi N. Singer, Alan D. Howard, David E. Trilling, E. Bernardoni, Ross A. Beyer, Ralph L. McNutt, D. Borncamp, John Stansberry, Simon B. Porter, Chloe B. Beddingfield, L. H. Wasserman, Bonnie J. Buratti, J. T. Keane, C. Fuentes, Ivan Linscott, Anne J. Verbiscer, Jean-Marc Petit, D. E. Jennings, A. L. Chaikin, Paul M. Schenk, Leslie A. Young, M. R. Piquette, Marc W. Buie, Catherine B. Olkin, Carly Howett, Mihaly Horanyi, Tod R. Lauer, Veronica J. Bray, Richard P. Binzel, Carey M. Lisse, Jeffrey M. Moore, Scott S. Sheppard, Silvia Protopapa, J. R. Spencer, William B. McKinnon, A. Y. Abedin, Kirby Runyon, G. R. Gladstone, S. A. Stern, Tetsuharu Fuse, Susan D. Benecchi, Rajani D. Dhingra, I. N. Reid, Mohamed Ramy El-Maarry, Martin Pätzold, H. A. Elliott, Amanda M. Zangari, Jason D. Hofgartner, H. Karoji, T. Stryk, Henry B. Throop, M. J. Kinczyk, Matthew J. Holman, David E. Kaufmann, A. F. Cheng, Daniel T. Britt, David J. McComas, David J. Tholen, Southwest Research Institute [Boulder] (SwRI), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Massachusetts Institute of Technology (MIT), Southwest Research Institute [San Antonio] (SwRI), Lowell Observatory [Flagstaff], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Princeton University, Rhenish Institute for Environmental Research (RIU), University of Cologne, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Flagstaff], and Northern Arizona University [Flagstaff]

Subjects
Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Contact binary, 01 natural sciences, Impact crater, Neptune, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, Spacecraft, business.industry, Geophysics, Radius, Accretion (astrophysics), es, 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System, business, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

Examining Arrokoth The New Horizons spacecraft flew past the Kuiper Belt object (486958) Arrokoth (also known as 2014 MU 69 ) in January 2019. Because of the great distance to the outer Solar System and limited bandwidth, it will take until late 2020 to downlink all the spacecraft's observations back to Earth. Three papers in this issue analyze recently downlinked data, including the highest-resolution images taken during the encounter (see the Perspective by Jewitt). Spencer et al. examined Arrokoth's geology and geophysics using stereo imaging, dated the surface using impact craters, and produced a geomorphological map. Grundy et al. investigated the composition of the surface using color imaging and spectroscopic data and assessed Arrokoth's thermal emission using microwave radiometry. McKinnon et al. used simulations to determine how Arrokoth formed: Two gravitationally bound objects gently spiraled together during the formation of the Solar System. Together, these papers determine the age, composition, and formation process of the most pristine object yet visited by a spacecraft. Science , this issue p. eaay3999 , p. eaay3705 , p. eaay6620 ; see also p. 980

Published
2020

23. Disk-resolved Photometric Properties of Pluto and the Coloring Materials across its Surface

Author

Thomas Gautier, Catherine B. Olkin, Simon B. Porter, Leslie A. Young, Kim Ennico, Alan Stern, Dale P. Cruikshank, Jian-Yang Li, Jason C. Cook, Francesca Scipioni, Eric Quirico, Kelsi N. Singer, Ross A. Beyer, H. A. Weaver, Carly Howett, Anne J. Verbiscer, Silvia Protopapa, Cristina M. Dalle Ore, William M. Grundy, Dennis C. Reuter, Southwest Research Institute [Boulder] (SwRI), Lowell Observatory [Flagstaff], Planetary Science Institute [Tucson] (PSI), University of Virginia [Charlottesville], NASA Ames Research Center (ARC), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Pinhead Institute, NASA Goddard Space Flight Center (GSFC), Search for Extraterrestrial Intelligence Institute (SETI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, Tholin, Astrophysics, Albedo, 01 natural sciences, Spectral line, Pluto, Atmosphere, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Spectral slope, 010303 astronomy & astrophysics, Radiometric calibration, 0105 earth and related environmental sciences
Abstract

International audience; A multiwavelength regionally dependent photometric analysis of Pluto's anti-Charon-facing hemisphere using images collected by New Horizons' Multispectral Visible Imaging Camera (MVIC) reveals large variations in the absolute value and spectral slope of the single-scattering albedo. Four regions of interest are analyzed: the dark equatorial belt, Pluto's north pole, nitrogen-rich regions, and the mid-latitude terrains. Regions dominated by volatile ices such as Lowell Regio and Sputnik Planitia present single-scattering albedos of ~0.98 at 492 nm, almost neutral across MVIC's visible wavelength range (400–910 nm), indicating limited contributions from tholin materials. Pluto's dark equatorial regions, informally named Cthulhu and Krun Maculae, have single-scattering albedos of ~0.16 at 492 nm and are the reddest regions. Applying the Hapke radiative transfer model to combined MVIC and Linear Etalon Imaging Spectral Array (LEISA) spectra (400–2500 nm) of Cthulhu Macula and Lowell Regio successfully reproduces the spectral properties of these two regions of dramatically disparate coloration, composition, and morphology. Since this model uses only a single coloring agent, very similar to the Titan-like tholin of Khare et al., to account for all of Pluto's colors, this result supports the Grundy et al. conclusion that Pluto's coloration is the result of photochemical products mostly produced in the atmosphere. Although cosmic rays and extreme ultraviolet photons reach Pluto's surface where they can drive chemical processing, observations of diverse surface colors do not require different chemical products produced in different environments. We report a correction scaling factor in the LEISA radiometric calibration of 0.74 ± 0.05.

Published
2020

24. Color, Composition, and Thermal Environment of Kuiper Belt Object (486958) Arrokoth

Author

Catherine B. Olkin, Dale P. Cruikshank, Simon B. Porter, Orkan M. Umurhan, Allen Lunsford, Silvia Protopapa, M. Ruaud, James Tuttle Keane, A. F. Cheng, Alex Parker, Mihaly Horanyi, Eric Quirico, Mark R. Showalter, Jeffrey M. Moore, D. E. Jennings, G. R. Gladstone, Francesca Scipioni, Bernard Schmitt, Amanda M. Zangari, Matthew E. Hill, Carly Howett, Ralph L. McNutt, S. A. Stern, John R. Spencer, William B. McKinnon, Marc W. Buie, L. Gabasova, Paul M. Schenk, D. C. Reuter, Kelsi N. Singer, G. Weigle, Anne J. Verbiscer, Joel Wm. Parker, Daniel T. Britt, Michael K. Bird, David J. McComas, H. A. Weaver, Leslie A. Young, H. A. Elliott, A. M. Earle, Yvonne J. Pendleton, Richard P. Binzel, Jason C. Cook, Ivan Linscott, William M. Grundy, Sebastiaan Krijt, C. M. Dalle Ore, Bonnie J. Buratti, Jj Kavelaars, Lowell Observatory [Flagstaff], NASA Ames Research Center (ARC), Southwest Research Institute [Boulder] (SwRI), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), French Centre National d'Etudes Spatiales (CNES), and Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Subjects
Solar System, Materials science, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, chemistry.chemical_element, FOS: Physical sciences, Radiation, 01 natural sciences, Spectral line, Methane, Kuiper belt, chemistry.chemical_compound, ices, Arrokoth, 0103 physical sciences, Thermal, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, 2014 MU69, methanol, Earth and Planetary Astrophysics (astro-ph.EP), CH3OH, Multidisciplinary, surface composition, New Horizons spacecraft, color, chemistry, 13. Climate action, Brightness temperature, Astrophysics::Earth and Planetary Astrophysics, Carbon, Microwave, Astrophysics - Earth and Planetary Astrophysics
Abstract

The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU69) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, which suggests that Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29 ± 5 kelvin. ©2020, NASA (contract no. NASW-02008), NASA (grant no. NAS5-97271 / TaskOrder30)

Published
2020
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25. Evaluation of short-term temporal evolution of Pluto’s surface composition from 2014–2017 with APO/TripleSpec

Author

Silvia Protopapa, Nancy J. Chanover, Leslie A. Young, A. J. Verbiscer, Bryan J. Holler, M. D. Yanez, and William M. Grundy

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Northern Hemisphere, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spectral line, Latitude, Pluto, Space and Planetary Science, Observatory, Solstice, Sublimation (phase transition), Absorption (electromagnetic radiation), Astrophysics - Earth and Planetary Astrophysics
Abstract

In this work we present the results of a spectral observing campaign of Pluto to search for temporal changes in surface composition on 1- to 3-year timescales. Near-infrared spectra of Pluto were obtained from June 2014 to August 2017 with the TripleSpec cross-dispersed spectrograph at the Apache Point Observatory's 3.5-meter Astrophysical Research Consortium (ARC) telescope. Observations were requested in order to obtain spectra of approximately the same sub-observer hemisphere $\sim$14 months apart, thus removing the effects of viewing geometry and rotation phase. Comparison of the CH$_4$ (methane) band areas and band center shifts between each component of these "matched pairs" revealed a surface in transition. Band areas for the 1.66 and 1.72 $\mu$m CH$_4$ absorption features exhibited a $>$5-$\sigma$ increase between 2014-06-17 and 2015-08-19, corresponding to a sub-observer hemisphere centered at $\sim$280$^{\circ}$E, with the latter date only 1 month after the New Horizons flyby of Pluto. The majority of matched pairs were obtained of the anti-Charon hemisphere, home to the bright, volatile-rich Sputnik Planitia, and did not present statistically significant changes in CH$_4$ band areas. CH$_4$ band center shifts, which provide information on the mixing state of CH$_4$ and N$_2$ in solid solution, were calculated between components of each matched pair, with no significant band shifts detected. The favored explanation for these combined results is the sublimation of more-volatile N$_2$ from the northern latitudes of Pluto in the lead-up to northern hemisphere summer solstice in 2029, leading to an increase in CH$_4$ concentration., Comment: 28 pages, 8 figures, 5 tables

Published
2022

26. Distribution and Energy Balance of Pluto's Nitrogen Ice, as seen by New Horizons in 2015

Author

Kimberly Ennico, Bernard Schmitt, William M. Grundy, Harold A. Weaver, Leslie A. Young, B. L. Lewis, Silvia Protopapa, John Stansberry, Bryan J. Holler, S. Alan Stern, Catherine B. Olkin, Carey M. Lisse, Department of Astronomy, Columbia University, Space Telescope Science Institute (STSci), Lowell Observatory [Flagstaff], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Southwest Research Institute [Boulder] (SwRI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), and NASA Ames Research Center (ARC)

Subjects
010504 meteorology & atmospheric sciences, Vapor pressure, Energy balance, Pluto: albedo, Volatile, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, chemistry.chemical_element, Atmospheric sciences, 01 natural sciences, Methane, Low emissivity, chemistry.chemical_compound, 0103 physical sciences, Emissivity, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Pluto, Astronomy and Astrophysics, Nitrogen, Pluto: atmosphere, chemistry, 13. Climate action, Space and Planetary Science, Environmental science, Sublimation (phase transition), Pluto: surface, Astrophysics - Earth and Planetary Astrophysics
Abstract

Pluto’s surface is geologically complex because of volatile ices that are mobile on seasonal and longer time scales. Here we analyzed New Horizons LEISA spectral data to globally map the nitrogen ice, including nitrogen with methane diluted in it. Our goal was to learn about the seasonal processes influencing ice redistribution, to calculate the globally averaged energy balance, and to place a lower limit on Pluto’s N 2 inventory. We present the average latitudinal distribution of nitrogen and investigate the relationship between its distribution and topography on Pluto by using maps that include the shifted bands of methane in solid solution with nitrogen (which are much stronger than the 2.15- μ m nitrogen band) to more completely map the distribution of the nitrogen ice. We find that the global average bolometric albedo is 0 . 83 ± 0 . 11 , similar to that inferred for Triton, and that a significant fraction of Pluto’s N 2 is stored in Sputnik Planitia. We also used the encounter-hemisphere distribution of nitrogen ice to infer the latitudinal distribution of nitrogen over the rest of Pluto, allowing us to calculate the global energy balance. Under the assumption that Pluto’s nitrogen-dominated 11.5 μ bar atmosphere is in vapor pressure equilibrium with the nitrogen ice, the ice temperature is 36 . 93 ± 0 . 10 K, as measured by New Horizons’ REX instrument. Combined with our global energy balance calculation, this implies that the average bolometric emissivity of Pluto’s nitrogen ice is probably in the range 0.47–0.72. This is consistent with the low emissivities estimated for Triton based on Voyager results, and may have implications for Pluto’s atmospheric seasonal variations, as discussed below. The global pattern of volatile transport at the time of the encounter was from north to south, and the transition between condensation and sublimation within Sputnik Planitia is correlated with changes in the grain size and CH 4 concentration derived from the spectral maps. The low emissivity of Pluto’s N 2 ice suggests that Pluto’s atmosphere may undergo an extended period of constant pressure even as Pluto recedes from the Sun in its orbit.

Published
2019

27. The nitrogen cycles on Pluto over seasonal and astronomical timescales

Author

Orkan M. Umurhan, Tanguy Bertrand, Paul M. Schenk, Harold A. Weaver, Catherine B. Olkin, Oliver L. White, Bernard Schmitt, Leslie A. Young, Silvia Protopapa, Kimberly Ennico, François Forget, Alan Stern, William M. Grundy, Kelsi N. Singer, Amanda M. Zangari, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), NASA Ames Research Center (ARC), Lowell Observatory [Flagstaff], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Southwest Research Institute [Boulder] (SwRI), Lunar and Planetary Institute [Houston] (LPI), and Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)

Subjects
Sputnik Planitia, 010504 meteorology & atmospheric sciences, Nitrogen, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Structural basin, 01 natural sciences, Latitude, Longitude of the periapsis, Paleo Modeling, Paleontology, ices, 0103 physical sciences, Glacial period, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Pluto, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Glacier, GCM, 13. Climate action, Space and Planetary Science, Sublimation (phase transition), Ice sheet, Geology
Abstract

International audience; Pluto’s landscape is shaped by the endless condensation and sublimation cycles of the volatile ices covering its surface. In particular, the Sputnik Planitia ice sheet, which is thought to be the main reservoir of nitrogen ice, displays a large diversity of terrains, with bright and dark plains, small pits and troughs, topographic depressions and evidences of recent and past glacial flows. Outside Sputnik Planitia, New Horizons also revealed numerous nitrogen ice deposits, in the eastern side of Tombaugh Regio and at mid-northern latitudes.These observations suggest a complex history involving volatile and glacial processes occurring on different timescales. We present numerical simulations of volatile transport on Pluto performed with a model designed to simulate the nitrogen cycle over millions of years, taking into account the changes of obliquity, solar longitude of perihelion and eccentricity as experienced by Pluto. Using this model, we first explore how the volatile and glacial activity of nitrogen within Sputnik Planitia has been impacted by the diurnal, seasonal and astronomical cycles of Pluto. Results show that the obliquity dominates the N 2 cycle and that over one obliquity cycle, the latitudes of Sputnik Planitia between 25 °S-30 °N are dom- inated by N 2 condensation, while the northern regions between 30 °N and -50 °N are dominated by N 2 sublimation. We find that a net amount of 1 km of ice has sublimed at the northern edge of Sputnik Planitia during the last 2 millions of years. It must have been compensated by a viscous flow of the thick ice sheet. By comparing these results with the observed geology of Sputnik Planitia, we can relate the formation of the small pits and the brightness of the ice at the center of Sputnik Planitia to the subli- mation and condensation of ice occurring at the annual timescale, while the glacial flows at its eastern edge and the erosion of the water ice mountains all around the ice sheet are instead related to the as- tronomical timescale. We also perform simulations including a glacial flow scheme which shows that the Sputnik Planitia ice sheet is currently at its minimum extent at the northern and southern edges. We also explore the stability of N 2 ice deposits outside the latitudes and longitudes of the Sputnik Planitia basin. Results show that N 2 ice is not stable at the poles but rather in the equatorial regions, in particu- lar in depressions, where thick deposits may persist over tens of millions of years, before being trapped in Sputnik Planitia. Finally, another key result is that the minimum and maximum surface pressures ob- tained over the simulated millions of years remain in the range of milli-Pascals and Pascals, respectively. This suggests that Pluto never encountered conditions allowing liquid nitrogen to flow directly on its sur- face. Instead, we suggest that the numerous geomorphological evidences of past liquid flow observed on Pluto’s surface are the result of liquid nitrogen that flowed at the base of thick ancient nitrogen glaciers, which have since disappeared.

Published
2018

28. Nondetection of Water-ice Grains in the Coma of Comet 46P/Wirtanen and Implications for Hyperactivity

Author

Bin Yang, Charles E. Woodward, Silvia Protopapa, and Michael S. Kelley

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Geophysics, Space and Planetary Science, Comet, Earth and Planetary Sciences (miscellaneous), FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Water ice, Astrophysics - Earth and Planetary Astrophysics, Astrobiology
Abstract

Hyperactive comets have high water production rates, with inferred sublimation areas of order the surface area of the nucleus. Comets 46P/Wirtanen and 103P/Hartley 2 are two examples of this cometary class. Based on observations of comet Hartley 2 by the Deep Impact spacecraft, hyperactivity appears to be caused by the ejection of water-ice grains and/or water-ice rich chunks of nucleus into the coma. These materials increase the sublimating surface area, and yield high water production rates. The historic close approach of comet Wirtanen to Earth in 2018 afforded an opportunity to test Hartley 2 style hyperactivity in a second Jupiter-family comet. We present high spatial resolution, near-infrared spectroscopy of the inner coma of Wirtanen. No evidence for the 1.5- or 2.0-$\mu$m water-ice absorption bands is found in six 0.8-2.5 $\mu$m spectra taken around perihelion and closest approach to Earth. In addition, the strong 3.0-$\mu$m water-ice absorption band is absent in a 2.0-5.3 $\mu$m spectrum taken near perihelion. Using spectroscopic and sublimation lifetime models we set constraints on the physical properties of the ice grains in the coma, assuming they are responsible for the comet's hyperactivity. We rule out pure water-ice grains of any size, given their long lifetime. Instead, the hyperactivity of the nucleus and lack of water-ice absorption features in our spectra can be explained either by icy grains on the order of 1 $\mu$m in size with a small amount of low albedo dust (greater than 0.5% by volume), or large chunks containing significant amounts of water ice., Comment: Accepted for publication in The Planetary Science Journal. 19 pages, 8 figures, 2 tables

Published
2021

29. Geological mapping of Sputnik Planitia on Pluto

Author

Paul M. Schenk, Orkan M. Umurhan, Harold A. Weaver, Tanguy Bertrand, Richard P. Binzel, Jeffrey M. Moore, Tod R. Lauer, Silvia Protopapa, William B. McKinnon, Alan D. Howard, Alissa M. Earle, Kelsi N. Singer, Ross A. Beyer, Oliver L. White, John R. Spencer, Kimberly Ennico, Andrew F. Cheng, Catherine B. Olkin, Stuart J. Robbins, Leslie A. Young, S. Alan Stern, Francis Nimmo, William M. Grundy, Bernard Schmitt, NASA Ames Research Center (ARC), Department of Earth and Planetary Sciences [St Louis], Washington University in Saint Louis (WUSTL), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA, Lunar and Planetary Institute [Houston] (LPI), Search for Extraterrestrial Intelligence Institute (SETI), Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), JHU APL, Southwest Research Institute [San Antonio] (SwRI), JHU/APL, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Earth Atmospheric and Planetary Sciences, MIT, Lowell Observatory [Flagstaff], National Optical Astronomy Observatory (NOAO), Department of Astronomy, University of Maryland, MD, USA, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Pluto, 010504 meteorology & atmospheric sciences, Ices, Astronomy and Astrophysics, Geologic map, 01 natural sciences, Mantle (geology), Astrobiology, Paleontology, Impact crater, [SDU]Sciences of the Universe [physics], Space and Planetary Science, 0103 physical sciences, surface, Geological processes, Glacial period, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

International audience; The geology and stratigraphy of the feature on Pluto informally named Sputnik Planitia is documented through geologic mapping at 1:2,000,000 scale. All units that have been mapped are presently being affected to some degree by the action of flowing N2 ice. The N2 ice plains of Sputnik Planitia display no impact craters, and are undergoing constant resurfacing via convection, glacial flow and sublimation. Condensation of atmospheric N2 onto the surface to form a bright mantle has occurred across broad swathes of Sputnik Planitia, and appears to be partly controlled by Pluto's obliquity cycles. The action of N2 ice has been instrumental in affecting uplands terrain surrounding Sputnik Planitia, and has played a key role in the disruption of Sputnik Planitia's western margin to form chains of blocky mountain ranges, as well in the extensive erosion by glacial flow of the uplands to the east of Sputnik Planitia.

Published
2017

30. Testing Tholins as Analogs of the Dark Reddish Material Covering the Cthulhu Region

Author

Marie Fayolle, Eric Quirico, Bernard Schmitt, Lora Jovanovic, Thomas Gautier, Nathalie Carrasco, Will Grundy, Veronique Vuitton, Olivier Poch, Leila Gabasova, Silvia Protopapa, Leslie Young, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Delft University of Technology (TU Delft), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Lowell Observatory [Flagstaff], Southwest Research Institute [Boulder] (SwRI), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Gautier, Thomas

Subjects
[SDU]Sciences of the Universe [physics], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Pluto's fly-by by the New Horizons spacecraft in July 2015 has revealed a dark reddish equatorial region (informally named Cthulhu). The non-icy material constituting the terrains of this region may have been formed from the sedimentation of aerosols [1,2]. Here, we investigate this hypothesis through the interpretation of the data collected by the visible imager (MVIC) and the near-infrared spectrometer (LEISA). Analogs (tholins) of Pluto's aerosols were synthesized in conditions that mimic Pluto's high atmosphere, and their optical properties were determined and used in Hapke models. We show that some of these tholins fit the reflectance level fairly well in the near-infrared, but don't match the shape of the red visible slope. In addition, several tholin bands are absent in LEISA observations, which might be due to a highly porous crust (formed from ice/tholin sublimation or microgravity), or to GCR irradiation. The first is our preferred interpretation.

Published
2019

31. Initial results from the New Horizons exploration of 2014 MU 69 , a small Kuiper Belt object

Author

J. Fischetti, S. Bhaskaran, Matthias Hahn, Karl Whittenburg, Derek S. Nelson, G. A. Griffith, Amanda M. Zangari, B. J. Buratti, James T. Keane, E. J. Lessac-Chenen, Ralph L. McNutt, Tiffany J. Finley, J. Scherrer, M. A. Ritterbush, M. M. Saina, G. Dunn, T. A. Hill, J. Van Eck, T. Stryk, J. M. Albers, D. C. Reuter, C. M. Dalle Ore, H. A. Elliott, D. J. Schultz, J. Andrews, Douglas P. Hamilton, M. H. Versteeg, Orkan M. Umurhan, Matthew E. Hill, Hai Nguyen, M. Simon, L. Gabasova, D. E. Jennings, D. J. Katz, J. E. Riedel, N. Behrooz, M. N. Fosbury, Henry B. Throop, A. J. Verbiscer, E. Bernardoni, Ross A. Beyer, C. Engelbrecht, Francesca Scipioni, H. L. Winters, Thomas H. Zurbuchen, Carey M. Lisse, Veronica J. Bray, M. G. Ryschkewitsch, Stuart J. Robbins, S. E. Jaskulek, M. C. Kochte, Thomas Mehoke, M. S. Lahr, M. J. Salinas, V. A. Mallder, S. P. Williams, B. H. May, D. M. Mages, C. C. Deboy, Simon B. Porter, Gerhard Kruizinga, Marc W. Buie, Jorge I. Nunez, John Hayes, Peter Kollmann, P. Dharmavaram, J. M. Moore, Darrell F. Strobel, John Stansberry, R. P. Binzel, H. M. Hart, Jillian Redfern, E. W. Stahlheber, H. K. Kang, James L. Green, Anthony F. Egan, Carly Howett, Fran Bagenal, Dale Stanbridge, Chris B. Hersman, C. L. Chavez, Debi Rose, J. Y. Pelgrift, Maria E. Banks, D. C. Schurr, Matthew R. Buckley, L. S. Turner, Ivan Linscott, Kaj E. Williams, J. Eisig, Mihaly Horanyi, Matthew Jones, Mark R. Showalter, William B. McKinnon, Leslie A. Young, E. J. Colwell, Daniel T. Britt, Kirby Runyon, David J. McComas, G. Weigle, Bernard Schmitt, Susan D. Benecchi, Alissa M. Earle, M. J. Kinczyk, Tod R. Lauer, M. R. Piquette, Lori S. Glaze, Carver J. Bierson, L. M. Burke, Brian Carcich, O. S. Custodio, A. Harch, Harold A. Weaver, Dale P. Cruikshank, Oliver L. White, L. E. Brown, William M. Grundy, G. K. Oxton, Chelsea L. Ferrell, David E. Kaufmann, Mohamed Ramy El-Maarry, K. A. Harmon, W. R. Schlei, Eric Quirico, Derek C. Richardson, J. M. Freeze, Jennifer Hanley, R. G. Shelton, Andrew J. Steffl, Mike Bird, H. W. Taylor, Harold J. Reitsema, Stamatios M. Krimigis, D. R. Boone, E. D. Fattig, A. L. Regiec, D. J. Rodgers, Jason D. Hofgartner, D. Velez, Catherine B. Olkin, Kelsi N. Singer, Brian Bauer, Carl J. Ercol, Martin Pätzold, Nicole Martin, Stewart Bushman, J. Firer, Allen W. Lunsford, R. W. Webbert, A. L. Chaikin, Alex Parker, C. A. Conrad, M. P. Conner, S. B. Cooper, Chloe B. Beddingfield, William M. Folkner, J. E. Lee, M. B. Tapley, G. R. Gladstone, D. A. Aguilar, Glen H. Fountain, Emma Birath, Rebecca Sepan, Jeremy Bauman, J. Wm. Parker, S. Weidner, J. R. Jensen, Jason C. Cook, Alan D. Howard, William M. Owen, Andrew F. Cheng, B. L. Enke, Sarah A. Hamilton, Tom Andert, K. B. Beisser, K. E. Bechtold, J. R. Wendel, Rajani D. Dhingra, Paul M. Schenk, Michael E. Summers, J. R. Spencer, D. W. Hals, Silvia Protopapa, A. C. Ocampo, Mark E. Holdridge, S. A. Stern, A. Taylor, R. M. Tedford, G. P. Keleher, Gabe Rogers, Frederic Pelletier, Jj Kavelaars, Yanping Guo, Jon Pineau, Steven J. Conard, Alice Bowman, A. Hosadurga, B. G. Williams, Michael Vincent, David Y. Kusnierkiewicz, Paul E. Rosendall, G. B. Lawrence, J. R. Stuart, M. M. Stothoff, Jr. D. S. Mehoke, Southwest Research Institute [Boulder] (SwRI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Lowell Observatory [Flagstaff], Space Physics Research Laboratory [Ann Arbor] (SPRL), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, SwRI Planetary Science Directorate [Boulder], Universitat de Lleida, Institut für Raumfahrttechnik, Universität der Bundeswehr München [Neubiberg], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Space Studies [Boulder], Rheinische Friedrich-Wilhelms-Universität Bonn, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institute of Hydrology, NASA Goddard Space Flight Center (GSFC), Department of Physics, Chemistry and Biology [Linköping] (IFM), Linköping University (LIU), Africa Rice Center [Bénin] (AfricaRice), Africa Rice Center [Côte d'Ivoire] (AfricaRice), Consultative Group on International Agricultural Research [CGIAR] (CGIAR)-Consultative Group on International Agricultural Research [CGIAR] (CGIAR), Yonsei University, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM), Princeton University, Reed College, Hanoi National University of Education (HNUE), Rhenish Institute for Environmental Research (RIU), University of Cologne, School of Earth, Atmospheric and Environmental Sciences [Manchester] (SEAES), University of Manchester [Manchester], ESA, Southwest Research Institute [San Antonio] (SwRI), NASA Ames Research Center (ARC), Laboratoire pour l'utilisation du rayonnement électromagnétique (LURE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-MENRT-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Johns Hopkins University (JHU), Institute of Physics of the Czech Academy of Sciences (FZU / CAS), Czech Academy of Sciences [Prague] (CAS), Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Department of Biochemistry, Faculty of Biology, University of Warmia and Mazury [Olsztyn], California Institute of Technology (CALTECH)-NASA, Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), University of Warmia and Mazury, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), inconnu temporaire UPEMLV, Inconnu, INGENIERIE (INGENIERIE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie des Procédés Plasmas et Traitement de Surface (ENSCP), PARIS, Africa Rice Center, Africa Rice Center (AfricaRice), Institut de pharmacologie moléculaire et cellulaire (IPMC), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics of Academy of Sciences of Czech Republic, and Czech Academy of Sciences [Prague] (ASCR)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Solar System, Multidisciplinary, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy, Coma (optics), Contact binary, Albedo, 01 natural sciences, Object (philosophy), Solar wind, 13. Climate action, 0103 physical sciences, Pebble, business, 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

The Kuiper Belt is a distant region of the Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a Cold Classical Kuiper Belt Object, a class of objects that have never been heated by the Sun and are therefore well preserved since their formation. Here we describe initial results from these encounter observations. MU69 is a bi-lobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color and compositional heterogeneity. No evidence for satellites, ring or dust structures, gas coma, or solar wind interactions was detected. By origin MU69 appears consistent with pebble cloud collapse followed by a low velocity merger of its two lobes., 43 pages, 8 figure

Published
2019

32. Kuiper Belt Object 2014MU 69 , Pluto and Phoebe as windows on the composition of the early solar nebula

Author

Stephan Stern, C. M. Dalle Ore, Y. J. Pendleton, Will Grundy, C. M. Lisse, Bernard Schmitt, Silvia Protopapa, Christopher K. Materese, Dale P. Cruikshank, NASA Ames Research Center (ARC), Southwest Research Institute [Boulder] (SwRI), Lowell Observatory [Flagstaff], NASA Goddard Space Flight Center (GSFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), and Centre National d'Etudes Spatiales (CNES)

Subjects
Nebula, Solar System, 010504 meteorology & atmospheric sciences, Solar Nebula, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Proto-planetary disk Models, Planetary system, 01 natural sciences, Astrobiology, Pluto, Stars, Methanol Ice, 13. Climate action, Space and Planetary Science, Saturn, 0103 physical sciences, Kuiper Belt Objects, Formation and evolution of the Solar System, 010303 astronomy & astrophysics, Chemical composition, Geology, 0105 earth and related environmental sciences
Abstract

The initial chemical composition of a proto-planetary nebula depends upon the degree to which 1) organic and ice components form on dust grains, 2) organic and molecular species form in the gas phase, 3) organics and ices are exchanged between the gas and solid state, and 4) the precursor and newly formed (more complex) materials survive and are modified in the developing planetary system. Infrared and radio observations of star-forming regions reveal that complex chemistry occurs on icy grains, often before stars even form. Additional processing, through the proto-planetary disk (PPD) further modifies most, but not all, of the initial materials. In fact, the modern Solar System still carries a fraction of its interstellar inheritance (Alexander et al.2017). Here we focus on three examples of small bodies in our Solar System, each containing chemical and dynamical clues to its origin and evolution: the small-cold classical Kuiper Belt object (KBO) 2014 MU69, Pluto, and Saturn’s moon, Phoebe. The New Horizons flyby of 2014 MU69 has given the first view of an unaltered body composed of material originally in the solar nebula at ~45 AU. The spectrum of MU69 reveals methanol ice (not commonly found), a possible detection of water ice, and the noteworthy absence of methane ice (Stern et al. 2019). Pluto’s internal and surface inventory of volatiles and complex organics, together with active geological processes including cryo-volcanism, indicate a surprising level of activity on a body in the outermost region of the Solar System, and the fluid that emerges from subsurface reservoirs may contain material inherited from the solar nebula (Cruikshank et al.2019a,b). Meanwhile, Saturn’s captured moon, Phoebe, carries high D/H in H2O (Clark et al. 2019) and complex organics (Cruikshank et al. 2008), both consistent with its formation in, and inheritance from, the outer region of the solar nebula. Together, these objects provide windows on the origin and evolution of our Solar System and constraints to be considered in future chemical and physical models of PPDs.

Published
2019

33. Persephone: A Pluto-system Orbiter and Kuiper Belt Explorer

Author

Jj Kavelaars, Mark E. Holdridge, Jon Pineau, Jani Radebaugh, Kelsi N. Singer, David H. Napolillo, Leslie A. Young, B. Andrews, William B. McKinnon, H. Nair, Clint Apland, Carolyn M. Ernst, Chris J. Krupiarz, Anne J. Verbiscer, Jack Hunt, Clint L. Edwards, Carly Howett, Blair D. Fonville, Adam Thodey, Silvia Protopapa, Adam V. Crifasi, Mark E. Perry, Dan Gallagher, Doug Crowley, Bruce Williams, Karl B. Fielhauer, Stuart J. Robbins, A. R. Hendrix, S. Alan Stern, Stewart Bushman, Orenthal J. Tucker, James S. Kuhn, Robert J. Wilson, Francis Nimmo, Heather Elliott, J. R. Spencer, David P. Frankford, Fazle E. Siddique, Simon B. Porter, Rachel Sholder, Samantha R. Walters, Bryan J. Holler, and J. C. Leary

Subjects
education.field_of_study, Spectrometer, Payload, Population, Astronomy and Astrophysics, Astrobiology, law.invention, Pluto, Jupiter, Orbiter, Geophysics, Space and Planetary Science, law, Earth and Planetary Sciences (miscellaneous), Gravity assist, Space Launch System, education, Geology
Abstract

Persephone is a NASA concept mission study that addresses key questions raised by New Horizons’ encounters with Kuiper Belt objects (KBOs), with arguably the most important being, “Does Pluto have a subsurface ocean?” More broadly, Persephone would answer four significant science questions: (1) What are the internal structures of Pluto and Charon? (2) How have the surfaces and atmospheres in the Pluto system evolved? (3) How has the KBO population evolved? (4) What are the particles and magnetic field environments of the Kuiper Belt? To answer these questions, Persephone has a comprehensive payload, and it would both orbit within the Pluto system and encounter other KBOs. The nominal mission is 30.7 yr long, with launch in 2031 on a Space Launch System Block 2 rocket with a Centaur kick stage, followed by a 27.6 yr cruise powered by existing radioisotope electric propulsion and a Jupiter gravity assist to reach Pluto in 2058. En route to Pluto, Persephone would have one 50–100 km class KBO encounter before starting a 3.1-Earth-year orbital campaign of the Pluto system. The mission also includes the potential for an 8 yr extended mission, which would enable the exploration of another KBO in the 100–150 km size class. The mission payload includes 11 instruments: Panchromatic and Color High-Resolution Imager, Low-Light Camera, Ultra-Violet Spectrometer, Near-Infrared (IR) Spectrometer, Thermal IR Camera, Radio Frequency Spectrometer, Mass Spectrometer, Altimeter, Sounding Radar, Magnetometer, and Plasma Spectrometer. The nominal cost of this mission is $3.0 billion, making it a large strategic science mission.

Published
2021

34. Testing Short-term Variability and Sampling of Primary Volatiles in Comet 46P/Wirtanen

Author

Ronald J. Vervack, Mohammad Saki, Michael R. Combi, Michael A. DiSanti, Martin A. Cordiner, Adam J. McKay, Nicolas Fougere, Hideyo Kawakita, Erika L. Gibb, Yinsi Shou, Silvia Protopapa, Nathan Roth, Younas Khan, Neil Dello Russo, and Boncho P. Bonev

Subjects
Geophysics, Primary (chemistry), Space and Planetary Science, Comet, Short Term Variability, Earth and Planetary Sciences (miscellaneous), Sampling (statistics), Environmental science, Astronomy and Astrophysics, Molecular spectroscopy, Astrobiology
Abstract

The exceptionally favorable close approach of Jupiter-family comet 46P/Wirtanen in 2018 December enabled characterization of its primary volatile composition with exceptionally high spatial resolution and sensitivities using the iSHELL spectrograph at the NASA Infrared Telescope Facility on Maunakea, HI. We sampled emissions from H2O, HCN, C2H2, NH3, C2H6, and CH3OH on UT 2018 December 21 using two instrumental settings that spanned the 2.9–3.6 μm spectral region. We also obtained a sensitive 3σ upper limit for H2CO and for the rarely studied molecule HC3N. We report rotational temperatures, production rates, and mixing ratios (relative to H2O as well as to C2H6). We place our results in context by comparing them with other comets observed at near-IR wavelengths. We also compare our results with those obtained using the NIRSPEC-2 spectrograph on Keck II on UT December 17 and 18 and with results obtained from iSHELL on other dates during the same apparition. Within 1–2σ uncertainty, production rates obtained for all molecules in this work were consistent with those obtained using NIRSPEC-2 except H2O, indicating low-level variability on a timescale of days. Mixing ratios with respect to H2O in 46P/Wirtanen were consistent with corresponding values from NIRSPEC-2 within the uncertainty with the exception of CH3OH, which yielded a higher ratio on December 21. Our measurements afforded a high temporal resolution that spanned ∼2/3 of the rotational period of 46P/Wirtanen, enabling us to test short-term variability in the production rates of H2O and HCN due to rotational effects. Both H2O and HCN production rates showed similar temporal variability, resulting in nearly constant HCN/H2O.

Published
2021

35. Searching for water ice in the coma of interstellar object 2I/Borisov

Author

Jacqueline V. Keane, Bin Yang, Silvia Protopapa, Schelte J. Bus, Michael S. P. Kelley, and Karen J. Meech

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Solar System, 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, 01 natural sciences, Spectral line, law.invention, Telescope, Space and Planetary Science, Planet, law, 0103 physical sciences, Spectral slope, 010303 astronomy & astrophysics, Spectrograph, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

Interstellar Objects (ISO) passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems. The main objective of our study is to search for diagnostic absorption features of water ice in the near infrared (NIR) spectrum of the second interstellar object 2I/2019 Q4 (Borisov) and compare its ice features to those of the Solar system icy objects. We observed 2I in the NIR on three separate occasions. The first observation was made on 2019 September 19 UT using the SpeX spectrograph at the 3-m IRTF and again on September 24 UT with the GNIRS spectrograph at the 8-m GEMINI telescope and the last observation was made on October 09 UT with IRTF. The spectra obtained from all three nights appear featureless. No absorption features associated with water ice are detected. Spectral modeling suggests that water grains, if present, comprise no more than 10% of the coma cross-section. The comet consistently exhibits a red D-type like spectrum with a spectral slope of about 6% per 100nm, which is similar to that of 1I/'Oumuamua and is comparable to Solar system comets., Comment: 5 pages, 4 figures, accepted for publication in A&A Letter

Published
2020

36. Icy Grains from the Nucleus of Comet C/2013 US10 (Catalina)

Author

James Bauer, Jacqueline V. Keane, Silvia Protopapa, Jessica M. Sunshine, Bin Yang, Charles E. Woodward, Michael S. P. Kelley, and Ludmilla Kolokolova

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Comet, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, medicine.anatomical_structure, Space and Planetary Science, 0103 physical sciences, Radiative transfer, medicine, 010303 astronomy & astrophysics, Nucleus, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present IRTF/SpeX and NEOWISE observations of the dynamically new comet C/2013 US$_{10}$ (Catalina), hereafter US10, from 5.8 au inbound, to near perihelion at 1.3 au, and back to 5.0 au outbound. We detect water ice in the coma of US10, assess and monitor the physical properties of the ice as insolation varies with heliocentric distance, and investigate the relationship between water ice and CO$_{2}$. This set of measurements is unique in orbital coverage and can be used to infer the physical evolution of the ice and, potentially, the nucleus composition. We report (1) nearly identical near-infrared spectroscopic measurements of the coma at $-$5.8 au, $-$5.0 au, +3.9 au (where $=3.9 au, the ice grains are long-lived and may be unchanged since leaving the comet nucleus. We find the nucleus of comet US10 is made of, among other components, $\sim$1-micron water-ice grains containing up to 1% refractory materials., Comment: Accepted for publication in ApJ Letters, 12 pages, 4 figures

Published
2018

37. Absorption coefficients of the methane–nitrogen binary ice system: Implications for Pluto

Author

Stephen C. Tegler, Silvia Protopapa, William M. Grundy, and J.M. Bergonio

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Materials science, 010504 meteorology & atmospheric sciences, Thermodynamic equilibrium, Analytical chemistry, FOS: Physical sciences, Infrared spectroscopy, chemistry.chemical_element, Astronomy and Astrophysics, 01 natural sciences, Nitrogen, Methane, Astrobiology, chemistry.chemical_compound, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Mixing ratio, Absorption (chemistry), 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Phase diagram, Solid solution
Abstract

The methane–nitrogen phase diagram of Prokhvatilov and Yantsevich (1983. Sov. J. Low Temp. Phys. 9, 94–98) indicates that at temperatures relevant to the surfaces of icy dwarf planets like Pluto, two phases contribute to the methane absorptions: nitrogen saturated with methane N 2 ‾ : CH 4 and methane saturated with nitrogen CH 4 ‾ : N 2 . No optical constants are available so far for the latter component limiting construction of a proper model, in compliance with thermodynamic equilibrium considerations. New optical constants for solid solutions of methane diluted in nitrogen ( N 2 : CH 4 ) and nitrogen diluted in methane ( CH 4 : N 2 ) are presented at temperatures between 40 and 90 K, in the wavelength range 1.1–2.7 μm at different mixing ratios. These optical constants are derived from transmission measurements of crystals grown from the liquid phase in closed cells. A systematic study of the changes of methane and nitrogen solid mixtures spectral behavior with mixing ratio and temperature is presented.

Published
2015

38. On the rotation period and shape of the hyperbolic asteroid 1I/'Oumuamua (2017) U1 from its lightcurve

Author

Matthew M. Knight, D. Bodewits, Jessica M. Sunshine, James M. Bauer, Michael S. P. Kelley, Lori M. Feaga, Silvia Protopapa, and Tony L. Farnham

Subjects
Physics, Rotation period, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Axial ratio, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, Rotation, 01 natural sciences, law.invention, Telescope, Amplitude, Space and Planetary Science, Asteroid, law, 0103 physical sciences, 010303 astronomy & astrophysics, Minor planet, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We observed the newly discovered hyperbolic minor planet 1I/`Oumuamua (2017 U1) on 2017 October 30 with Lowell Observatory's 4.3-m Discovery Channel Telescope. From these observations, we derived a partial lightcurve with peak-to-trough amplitude of at least 1.2 mag. This lightcurve segment rules out rotation periods less than 3 hr and suggests that the period is at least 5 hr. On the assumption that the variability is due to a changing cross section, the axial ratio is at least 3:1. We saw no evidence for a coma or tail in either individual images or in a stacked image having an equivalent exposure time of 9000 s., Updated in response to referee's comments. Accepted by ApJL

Published
2017

39. Near-UV OH Prompt Emission in the Innermost Coma of 103P/Hartley 2

Author

Michael S. P. Kelley, Jessica M. Sunshine, Michael F. A'Hearn, Silvia Protopapa, Fiorangela La Forgia, Lori M. Feaga, Dennis Bodewits, and Tony L. Farnham

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Jet (fluid), 010504 meteorology & atmospheric sciences, comets: individual (103P/Hartley 2), methods: data analysis, techniques: photometric, Resolution (electron density), Photodissociation, Comet, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, 01 natural sciences, Fluorescence, Space and Planetary Science, Excited state, 0103 physical sciences, 010303 astronomy & astrophysics, Water vapor, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

The Deep Impact spacecraft fly-by of comet 103P/Hartley 2 occurred on 2010 November 4, one week after perihelion with a closest approach (CA) distance of about 700 km. We used narrowband images obtained by the Medium Resolution Imager (MRI) onboard the spacecraft to study the gas and dust in the innermost coma. We derived an overall dust reddening of 15\%/100 nm between 345 and 749 nm and identified a blue enhancement in the dust coma in the sunward direction within 5 km from the nucleus, which we interpret as a localized enrichment in water ice. OH column density maps show an anti-sunward enhancement throughout the encounter except for the highest resolution images, acquired at CA, where a radial jet becomes visible in the innermost coma, extending up to 12 km from the nucleus. The OH distribution in the inner coma is very different from that expected for a fragment species. Instead, it correlates well with the water vapor map derived by the HRI-IR instrument onboard Deep Impact \citep{AHearn2011}. Radial profiles of the OH column density and derived water production rates show an excess of OH emission during CA that cannot be explained with pure fluorescence. We attribute this excess to a prompt emission process where photodissociation of H$_2$O directly produces excited OH*($A^2\it{\Sigma}^+$) radicals. Our observations provide the first direct imaging of Near-UV prompt emission of OH. We therefore suggest the use of a dedicated filter centered at 318.8 nm to directly trace the water in the coma of comets., Comment: 21 pages

Published
2017
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40. The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission

Author

Benoit Carry, M. F. A'Hearn, Sebastien Besse, Michaël Gillon, M. J. Mumma, Galin Borisov, B. Rajkumar, Janet E. Drew, Olga Muñoz, Viktor Afanasiev, Tarik Zegmott, Lucas Paganini, D. Bodewits, Rita Schulz, Emily Kramer, Adam J. McKay, Diane H. Wooden, J. de León, Michael Schmidt, Geraint H. Jones, S. Haque, Andrew McNeill, Fernando Moreno, Sara Faggi, P. J. Gutiérrez, Jérémie Lasue, Aurélie Guilbert-Lepoutre, J. M. Sunshine, Javier Licandro, Zhong-Yi Lin, Pedro Lacerda, Philippe Rousselot, Jose Luis Ortiz, Nicolas Biver, Marco Micheli, J. J. López-Moreno, Matthew M. Knight, Jon Marchant, Detlef Koschny, Dominik R. G. Schleicher, F. Aceituno, Michael S. P. Kelley, Colin Snodgrass, G. P. Tozzi, Michael A. DiSanti, Karen J. Meech, Olivier Hainaut, Alfredo Sota, Niklas J. T. Edberg, Edith Hadamcik, Rene Duffard, Rosita Kokotanekova, Erika L. Gibb, Damien Hutsemekers, E. Ramos, Y. Ramanjooloo, A. Guijarro, Ulrich Hopp, Luisa Lara, Stephen C. Lowry, Tim Lister, Anita L. Cochran, V. Casanova, Pablo Santos-Sanz, J. Kleyna, R. Hedrosa, M. Pajuelo, A. K. Sen, Cyrielle Opitom, Emmanuel Jehin, A. Thompson, Alan Fitzsimmons, Geronimo L. Villanueva, E. J. W. de Mooij, Stefano Bagnulo, C. Ries, Boncho P. Bonev, O. Ivanova, Amy Mainzer, John K. Davies, Blair C. Conn, Anny Chantal Levasseur-Regourd, P. Nikolov, Auni Somero, Nikolai Kiselev, Lori M. Feaga, Maria Monguió, Francisco J. Pozuelos, A. Stinson, M. Delacruz, Björn Davidsson, Jacqueline V. Keane, M. Kluge, Dean C. Hines, Simon F. Green, Jean Manfroid, James Bauer, Silvia Protopapa, M. de Val-Borro, T. Pursimo, Xiaobin Wang, Cecilia Tubiana, Hermann Boehnhardt, Masafumi Yagi, I. Mohammed, Vera Rosenbush, F. Hoyo, Harry Lehto, G. Bergond, B. Yang, Méabh Hyland, Arno Riffeser, Hideaki Fujiwara, Erin L. Ryan, B. Zaprudin, School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] ( OU ), Department of Astronomy [College Park], University of Maryland [College Park], Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Special Astrophysical Observatory of the Russian Academy of Sciences ( SAO ), Russian Academy of Sciences [Moscow] ( RAS ), Armagh Observatory [Armagh], Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), Centro Astronómico Hispano Alemán, European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Department of Physics [Washington], American University Washington D.C. ( AU ), Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Joseph Louis LAGRANGE ( LAGRANGE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), McDonald Observatory, University of Texas at Austin [Austin], Research School of Astronomy and Astrophysics [Canberra] ( RSAA ), Australian National University ( ANU ), Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy ( AURA ), UK Astronomy Technology Centre ( UK ATC ), Science and Technology Facilities Council ( STFC ), Universidad de La Laguna ( ULL ), Instituto de Astrofisica de Canarias ( IAC ), Astrophysics Research Centre [Belfast] ( ARC ), Queen's University [Belfast] ( QUB ), Catholic University of America, Astrochemistry Laboratory [Greenbelt], NASA Goddard Space Flight Center ( GSFC ), Department of Astrophysical Sciences [Princeton], Princeton University, Institute for Astronomy [Honolulu], University of Hawaii at Manoa ( UHM ), School of Physics, Astronomy and Mathematics [Hatfield], University of Hertfordshire [Hatfield] ( UH ), Swedish Institute of Space Physics [Uppsala] ( IRF ), National Astronomical Observatory of Japan ( NAOJ ), Department of Physics and Astronomy [Columbia], University of Missouri-Columbia, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), European Southern Observatory ( ESO ), Department of Physics [Trinidad], The University of the West Indies, Space Telescope Science Institute ( STSci ), Ludwig-Maximilians University [Munich] ( LMU ), Astronomical Institute of the Slovak Academy of Sciences, Slovak Academy of Science [Bratislava] ( SAS ), Mullard Space Science Laboratory ( MSSL ), University College of London [London] ( UCL ), Centre for Planetary Sciences [UCL/Birkbeck] ( CPS ), Main Astronomical Observatory of NAS of Ukraine ( MAO ), National Academy of Sciences of Ukraine ( NASU ), Research and Scientific Support Department, ESTEC ( RSSD ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ) -European Space Agency ( ESA ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Tuorla Observatory, University of Turku, Institute of Astronomy [Taiwan] ( IANCU ), National Central University [Taiwan] ( NCU ), Las Cumbres Observatory ( LCO ), Centre for Astrophysics and Planetary Science [Canterbury] ( CAPS ), University of Kent [Canterbury], Astrophysics Research Institute [Liverpool] ( ARI ), Liverpool John Moores University ( LJMU ), ESA SSA-NEO Coordination Centre, Caribbean Institute of Astronomy ( CARINA ), Pontificia Universidad Católica del Perú ( PUCP ), Nordic Optical Telescope ( NOT ), SETI Institute, Lowell Observatory [Flagstaff], European Space Agency, Scientific Support Office, Assam University, INAF - Osservatorio Astrofisico di Arcetri ( OAA ), Istituto Nazionale di Astrofisica ( INAF ), Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences [Beijing] ( CAS ), Yunnan Observatories, Chinese Academy of Sciences [Changchun Branch] ( CAS ), NASA Ames Research Center ( ARC ), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), University of Maryland System-University of Maryland System, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Special Astrophysical Observatory of the Russian Academy of Sciences (SAO), Russian Academy of Sciences [Moscow] (RAS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Centro Astronómico Hispano Alemán, Observatorio de Calar Alto (CAHA), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, American University Washington D.C. (AU), Institute of Astronomy of the Bulgarian Academy of Sciences, Bulgarian Academy of Sciences (BAS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), Association of Universities for Research in Astronomy (AURA), UK Astronomy Technology Centre (UK ATC), Science and Technology Facilities Council (STFC), Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), NASA Goddard Space Flight Center (GSFC), University of Hawai‘i [Mānoa] (UHM), University of Hertfordshire [Hatfield] (UH), Swedish Institute of Space Physics [Uppsala] (IRF), National Astronomical Observatory of Japan (NAOJ), Department of Physics and Astronomy [Columbia] (Mizzou Physics), University of Missouri [Columbia] (Mizzou), University of Missouri System-University of Missouri System, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Space Telescope Science Institute (STSci), Ludwig-Maximilians-Universität München (LMU), Slovak Academy of Science [Bratislava] (SAS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Centre for Planetary Sciences [UCL/Birkbeck] (CPS), Main Astronomical Observatory of NAS of Ukraine (MAO), National Academy of Sciences of Ukraine (NASU), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Las Cumbres Observatory (LCO), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Caribbean Institute of Astronomy (CARINA), Pontificia Universidad Católica del Perú (PUCP), Nordic Optical Telescope (NOT), ESA Scientific Support Office, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Chinese Academy of Sciences [Beijing] (CAS), Chinese Academy of Sciences [Changchun Branch] (CAS), NASA Ames Research Center (ARC), NASA-California Institute of Technology (CALTECH), Agence Spatiale Européenne = European Space Agency (ESA), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP)

Subjects
Future studies, History, 010504 meteorology & atmospheric sciences, General Mathematics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], General Physics and Astronomy, FOS: Physical sciences, Context (language use), 01 natural sciences, Astrobiology, Jupiter, 0103 physical sciences, 010303 astronomy & astrophysics, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), comet 67P/Churyumov?Gerasimenko, Rosetta, solar system, observational astronomy, ta115, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], General Engineering, Articles, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Early results, business, [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft, and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively `well behaved' comet, typical of Jupiter family comets and with activity patterns that repeat from orbit-to-orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends -- in this paper we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies., Comment: Author prepared version; final published version available at journal. 22 pages

Published
2017

41. Water ice and dust in the innermost coma of comet 103P/Hartley 2

Author

Michael S. P. Kelley, Jessica M. Sunshine, Jian-Yang Li, Olivier Groussin, Lori M. Feaga, Sebastien Besse, Michael F. A'Hearn, F. Merlin, Silvia Protopapa, Tony L. Farnham, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrometer, Comet dust, Comet, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spatial distribution, Spectral line, Grain size, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, Outflow, Astrophysics - Earth and Planetary Astrophysics
Abstract

On November 4th, 2010, the Deep Impact eXtended Investigation (DIXI) successfully encountered comet 103P/Hartley 2, when it was at a heliocentric distance of 1.06 AU. Spatially resolved near-IR spectra of comet Hartley 2 were acquired in the 1.05-4.83 micron wavelength range using the HRI-IR spectrometer. We present spectral maps of the inner ~10 kilometers of the coma collected 7 minutes and 23 minutes after closest approach. The extracted reflectance spectra include well-defined absorption bands near 1.5, 2.0, and 3.0 micron consistent in position, bandwidth, and shape with the presence of water ice grains. Using Hapke's radiative transfer model, we characterize the type of mixing (areal vs. intimate), relative abundance, grain size, and spatial distribution of water ice and refractories. Our modeling suggests that the dust, which dominates the innermost coma of Hartley 2 and is at a temperature of 300K, is thermally and physically decoupled from the fine-grained water ice particles, which are on the order of 1 micron in size. The strong correlation between the water ice, dust, and CO2 spatial distribution supports the concept that CO2 gas drags the water ice and dust grains from the nucleus. Once in the coma, the water ice begins subliming while the dust is in a constant outflow. The derived water ice scale-length is compatible with the lifetimes expected for 1-micron pure water ice grains at 1 AU, if velocities are near 0.5 m/s. Such velocities, about three order of magnitudes lower than the expansion velocities expected for isolated 1-micron water ice particles [Hanner, 1981; Whipple, 1951], suggest that the observed water ice grains are likely aggregates., Comment: 51 pages, 12 figures, accepted for publication in Icarus

Published
2014

42. Surface compositions across Pluto and Charon

Author

Dale P. Cruikshank, Marc W. Buie, William M. Grundy, John R. Spencer, C. M. Dalle Ore, Bonnie J. Buratti, J. Wm. Parker, Silvia Protopapa, Henry B. Throop, Andrew F. Cheng, Bernard Schmitt, C. C. C. Tsang, A. J. Verbiscer, Catherine B. Olkin, Allen W. Lunsford, Jason C. Cook, Leslie A. Young, Paul M. Schenk, John Stansberry, Harold A. Weaver, Ivan Linscott, Eric Quirico, Kimberly Ennico, S. Philippe, Kelsi N. Singer, D. E. Jennings, G. Weigle, Alissa M. Earle, Alex Parker, Ross A. Beyer, Carly Howett, D. C. Reuter, Richard P. Binzel, S. A. Stern, Lowell Observatory [Flagstaff], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), NASA Ames Research Center (ARC), Southwest Research Institute [Boulder] (SwRI), University of Victoria [Canada] (UVIC), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), NASA Goddard Space Flight Center (GSFC), and SwRI Planetary Science Directorate [Boulder]

Subjects
010504 meteorology & atmospheric sciences, Outcrop, FOS: Physical sciences, 01 natural sciences, Charon, Astrobiology, Latitude, Impact crater, 0103 physical sciences, Glacial period, Ejecta, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Pluton, geography, Multidisciplinary, geography.geographical_feature_category, Bedrock, Pluto, Surface, New Horizons mission, composition, [SDU]Sciences of the Universe [physics], Protoplanet, Astrophysics - Earth and Planetary Astrophysics
Abstract

The New Horizons spacecraft mapped colors and infrared spectra across the encounter hemispheres of Pluto and Charon. The volatile ices CH$_4$, CO, and N$_2$, that dominate Pluto's surface, have complicated spatial distributions resulting from sublimation, condensation, and glacial flow acting over seasonal and geological timescales. Pluto's H$_2$O ice "bedrock" is also mapped, with isolated outcrops occurring in a variety of settings. Pluto's surface exhibits complex regional color diversity associated with its distinct provinces. Charon's color pattern is simpler, dominated by neutral low latitudes and a reddish northern polar region. Charon near infrared spectra reveal highly localized areas with strong NH$_3$ absorption tied to small craters with relatively fresh-appearing impact ejecta., Comment: in Science 351, aad9189 (2016)

Published
2016

43. The small satellites of Pluto as observed by New Horizons

Author

Kimberly Ennico, G. R. Gladstone, Stuart J. Robbins, Jeffrey M. Moore, Mark R. Showalter, Silvia Protopapa, Constantine Tsang, Simon B. Porter, C. M. Dalle Ore, A. F. Cheng, Catherine B. Olkin, Kelsi N. Singer, Paul M. Schenk, Dennis C. Reuter, Michael E. Summers, D. E. Jennings, Alex Parker, T. Stryk, S. Philippe, Douglas P. Hamilton, William M. Grundy, S. A. Stern, John R. Spencer, Ivan Linscott, Carey M. Lisse, Tod R. Lauer, Francis Nimmo, Anne J. Verbiscer, Henry B. Throop, J. Wm. Parker, Carolyn M. Ernst, David E. Kaufmann, Oliver L. White, Jason C. Cook, Veronica J. Bray, Amanda M. Zangari, Dale P. Cruikshank, Allen Lunsford, Leslie A. Young, A. M. Earle, Harold A. Weaver, Olivier S. Barnouin, Harold J. Reitsema, Bonnie J. Buratti, William B. McKinnon, Marc W. Buie, Ross A. Beyer, Carly Howett, Bernard Schmitt, Richard P. Binzel, and A. L. Chaikin

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Multidisciplinary, New horizons, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy, 01 natural sciences, Pluto, Impact crater, Physics::Space Physics, 0103 physical sciences, Lernaean Hydra, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of $\approx$40 km for Nix and Hydra and ~10 km for Styx and Kerberos. They are also highly elongated, with maximum to minimum axis ratios of $\approx$2. All four moons have high albedos ( $\approx$50-90 %) suggestive of a water-ice surface composition. Crater densities on Nix and Hydra imply surface ages $\gtrsim$ 4 Ga. The small moons rotate much faster than synchronous, with rotational poles clustered nearly orthogonal to the common pole directions of Pluto and Charon. These results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary., Comment: in Science 351, aae0030 (2016)

Published
2016

44. The long-wavelength thermal emission of the Pluto-Charon system from Herschel observations. Evidence for emissivity effects

Author

Raphael Moreno, P. Panuzzo, John Stansberry, Esa Vilenius, Silvia Protopapa, Tanya Lim, Tamás Müller, Pablo Santos-Sanz, Sonia Fornasier, Gábor Marton, Cs. Kiss, Emmanuel Lellouch, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Max-Planck-Institut für Extraterrestrische Physik (MPE), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), TKK Helsinki University of Technology (TKK), Southwest Research Institute [Boulder] (SwRI), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Light curve, 01 natural sciences, Pluto, Wavelength, 13. Climate action, Space and Planetary Science, Asteroid, Brightness temperature, 0103 physical sciences, Emissivity, Penetration depth, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

Thermal observations of the Pluto-Charon system acquired by the Herschel Space Observatory in February 2012 are presented. They consist of photometric measurements with the PACS and SPIRE instruments (nine visits to the Pluto system each), covering six wavelengths from 70 to 500 $\mu$m altogether. The thermal light curve of Pluto-Charon is observed in all filters, albeit more marginally at 160 and especially 500 $\mu$m. Putting these data into the context of older ISO, Spitzer and ground-based observations indicates that the brightness temperature (T$_B$) of the system (rescaled to a common heliocentric distance) drastically decreases with increasing wavelength, from $\sim$53 K at 20 $\mu$m to $\sim$35 K at 500 $\mu$m, and perhaps ever less at longer wavelengths. Considering a variety of diurnal and/or seasonal thermophysical models, we show that T$_B$ values of 35 K are lower than any expected temperature for the dayside surface or subsurface of Pluto and Charon, implying a low surface emissivity. Based on multiterrain modeling, we infer a spectral emissivity that decreases steadily from 1 at 20-25 $\mu$m to $\sim$0.7 at 500~$\mu$m. This kind of behavior is usually not observed in asteroids (when proper allowance is made for subsurface sounding), but is found in several icy surfaces of the solar system. We tentatively identify that a combination of a strong dielectric constant and a considerable surface material transparency (typical penetration depth $\sim$1 cm) is responsible for the effect. Our results have implications for the interpretation of the temperature measurements by REX/New Horizons at 4.2 cm wavelength., Comment: 15 pages, 9 figures, 2 tables

Published
2016

45. Inflight Radiometric Calibration of New Horizons' Multispectral Visible Imaging Camera (MVIC)

Author

Ross A. Beyer, Bonnie J. Buratti, Carly Howett, R. P. Binzel, Silvia Protopapa, Joel Wm. Parker, Dale P. Cruikshank, G. Weigle, Harold A. Weaver, A.L. Graps, S. A. Stern, Paul M. Schenk, Alissa M. Earle, Marc W. Buie, Bernard Schmitt, S. Phillippe, Constantine Tsang, Alex Parker, Kelsi N. Singer, D. C. Reuter, C. M. Dalle Ore, Catherine B. Olkin, Andrew F. Cheng, Allen W. Lunsford, D. E. Jennings, Eric Quirico, K.P. Harrison, Simon B. Porter, John R. Spencer, Kimberly Ennico, Leslie A. Young, Jason C. Cook, William M. Grundy, Ivan Linscott, Henry B. Throop, J. R. Lovering, A. J. Verbiscer, and John Stansberry

Subjects
010504 meteorology & atmospheric sciences, Multispectral image, FOS: Physical sciences, Field of view, 01 natural sciences, Optics, 0103 physical sciences, Calibration, 010303 astronomy & astrophysics, Radiometric calibration, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), Pixel, business.industry, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Planetary Data System, Panchromatic film, Space and Planetary Science, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, business, Astrophysics - Earth and Planetary Astrophysics
Abstract

© 2016 Elsevier Inc. We discuss two semi-independent calibration techniques used to determine the inflight radiometric calibration for the New Horizons’ Multi-spectral Visible Imaging Camera (MVIC). The first calibration technique compares the measured number of counts (DN) observed from a number of well calibrated stars to those predicted using the component-level calibration. The ratio of these values provides a multiplicative factor that allows a conversation between the preflight calibration to the more accurate inflight one, for each detector. The second calibration technique is a channel-wise relative radiometric calibration for MVIC's blue, near-infrared and methane color channels using Hubble and New Horizons observations of Charon and scaling from the red channel stellar calibration. Both calibration techniques produce very similar results (better than 7% agreement), providing strong validation for the techniques used. Since the stellar calibration described here can be performed without a color target in the field of view and covers all of MVIC's detectors, this calibration was used to provide the radiometric keyword values delivered by the New Horizons project to the Planetary Data System (PDS). These keyword values allow each observation to be converted from counts to physical units; a description of how these keyword values were generated is included. Finally, mitigation techniques adopted for the gain drift observed in the near-infrared detector and one of the panchromatic framing cameras are also discussed.

Published
2016
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46. SURFACE COMPOSITIONS OF PLUTO AND CHARON

Author

S. Philippe, Jason C. Cook, Alissa M. Earle, Harold A. Weaver, D. C. Reuter, C. M. Dalle Ore, William M. Grundy, Kimberly Ennico, S. A. Stern, Catherine B. Olkin, Leslie A. Young, Dale P. Cruikshank, Richard P. Binzel, Silvia Protopapa, and Bernard Schmitt

Subjects
Surface (mathematics), Pluto, Materials science, Astrobiology
Published
2016

47. SPECTRAL ANALYSIS OF PLUTO'S WATER-ICE RICH SPOTS AT NEAR INFRARED WAVELENGTHS

Author

Kelsi N. Singer, J. A. Stansberry, R. P. Binzel, D. E. Jennings, Dale P. Cruikshank, Alex Parker, Alissa M. Earle, Bernard Schmitt, Silvia Protopapa, Cathy Olkin, Leslie A. Young, S. Philippe, C.J.Α. Howett, Allen W. Lunsford, D. C. Reuter, C. M. Dalle Ore, A. J. Verbiscer, Kimberly Ennico, Harold A. Weaver, S. Alan Stern, Jason C. Cook, and William M. Grundy

Subjects
Pluto, Wavelength, Spots, Near-infrared spectroscopy, Astronomy, Spectral analysis, Water ice, Geology, Astrobiology
Published
2016

48. WHAT HAVE WE LEARNED ABOUT CHARON FROM NEW HORIZONS?

Author

Ivan Linscott, D. C. Reuter, C. M. Dalle Ore, Tod R. Lauer, Mark R. Showalter, Dale P. Cruikshank, Bernard Schmitt, Amanda M. Zangari, R. P. Binzel, Stephan Stern, Cathy Olkin, J. Wm. Parker, C. M. Lisse, Allen W. Lunsford, Orkan M. Umurhan, A. J. Verbiscer, Harold A. Weaver, Francis Nimmo, G. L. Tyler, Harold J. Reitsema, Stuart J. Robbins, Ross A. Beyer, Kimberly Ennico, William M. Grundy, J. R. Spencer, J. A. Stansberry, C. C. C. Tsang, Leslie A. Young, D. E. Jennings, J. M. Moore, Kelsi N. Singer, S. Philippe, Jason C. Cook, C.J.Α. Howett, Francesca Scipioni, Veronica J. Bray, William B. McKinnon, K. L. Berry, Alissa M. Earle, Allen C. Cheng, R.I. Kaiser, Alex Parker, B. J. Buratti, Paul M. Schenk, Oliver L. White, Silvia Protopapa, Eric Quirico, and M. W. Buie

Subjects
New horizons, Astronomy, Geology, Astrobiology
Published
2016

49. Solar system science with the Wide-Field Infrared Survey Telescope

Author

Gordon L. Bjoraker, Tony L. Farnham, Bryan J. Holler, Dennis Bodewits, David Trilling, Silvia Protopapa, Amanda A. Sickafoose, Andrea Longobardo, Darin Ragozzine, Henry H. Hsieh, Michele T. Bannister, Amanda S. Bosh, Robert A. West, Vishnu Reddy, Nader Haghighipour, Marc W. Buie, Lynnae C. Quick, James Bauer, Paul S. Hardersen, Christopher M. Hirata, Michael S. P. Kelley, Conor A. Nixon, G. Sarid, Andrew S. Rivkin, Charles Alcock, Cristina A. Thomas, Stefanie N. Milam, Alan W. Harris, Ernesto Palomba, E. A. Kramer, Jason Rhodes, Matthew M. Knight, and Amy Simon

Subjects
Solar System, 010504 meteorology & atmospheric sciences, Mechanical Engineering, James Webb Space Telescope, Astronomy, Astronomy and Astrophysics, Large Synoptic Survey Telescope, 01 natural sciences, Electronic, Optical and Magnetic Materials, Spitzer Space Telescope, Space and Planetary Science, Control and Systems Engineering, Planet, Trojan, Asteroid, 0103 physical sciences, 010303 astronomy & astrophysics, Instrumentation, Geology, 0105 earth and related environmental sciences, Wide Field Infrared Survey Telescope
Abstract

We present a community-led assessment of the solar system investigations achievable with NASA’s next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μm and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg^2 field-of-view Wide Field Instrument. Potential ground-breaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations.

Published
2018

50. ESO large program about transneptunian objects: surface variations on (47171) 1999 TC36

Author

F. Merlin, G. P. Tozzi, S. Fornasier, A. Delsanti, M. A. Barucci, Silvia Protopapa, A. Alvarez-Candal, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA)

Subjects
Physics, Scattering, Astronomy and Astrophysics, Tholin, Astrophysics, Reflectivity, Spectral line, symbols.namesake, Atmospheric radiative transfer codes, Space and Planetary Science, Radiative transfer, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Visible spectrum
Abstract

International audience; Aims: We investigate the surface composition of the Plutino (47171) 1999 TC{36}. Methods: We completed near-infrared photometric and spectroscopic observations of (47171) 1999 TC{36} with the adaptive optics instrument NACO at the ESO VLT during 12 October 2006, and present these data with ISAAC and SINFONI spectroscopic observations carried out about one month later on 9 November 2006 and 8 November 2006, respectively. The ISAAC and SINFONI spectroscopic observations were combined with a visible spectrum obtained by FORS1 on 9 November 2006. Composition and properties of the compounds present on the surface of the target are investigated by applying a Hapke radiative transfer model to the measured spectra and to previously published observations. Results: We present the relative reflectance spectrum of (47171) 1999 TC{36} in the wavelength range (0.37-2.33) mum. An intimate mixture of Triton tholin, Titan tholin, serpentine, and Triton tholin diluted in water ice represents the best-fit model description of the measured spectrum. Any significant differences from the published spectra of (47171) 1999 TC{36} taken on 2001 and 2003 could be due to surface heterogeneity.

Published
2009

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