TY  - JOUR
A1  - Arridge, Christopher S.
A1  - Achilleos, N.
A1  - Agarwal, Jessica
A1  - Agnor, C. B.
A1  - Ambrosi, R.
A1  - Andre, N.
A1  - Badman, S. V.
A1  - Baines, K.
A1  - Banfield, D.
A1  - Barthelemy, M.
A1  - Bisi, M. M.
A1  - Blum, J.
A1  - Bocanegra-Bahamon, T.
A1  - Bonfond, B.
A1  - Bracken, C.
A1  - Brandt, P.
A1  - Briand, C.
A1  - Briois, C.
A1  - Brooks, S.
A1  - Castillo-Rogez, J.
A1  - Cavalie, T.
A1  - Christophe, B.
A1  - Coates, Andrew J.
A1  - Collinson, G.
A1  - Cooper, J. F.
A1  - Costa-Sitja, M.
A1  - Courtin, R.
A1  - Daglis, I. A.
A1  - De Pater, Imke
A1  - Desai, M.
A1  - Dirkx, D.
A1  - Dougherty, M. K.
A1  - Ebert, R. W.
A1  - Filacchione, Gianrico
A1  - Fletcher, Leigh N.
A1  - Fortney, J.
A1  - Gerth, I.
A1  - Grassi, D.
A1  - Grodent, D.
A1  - Grün, Eberhard
A1  - Gustin, J.
A1  - Hedman, M.
A1  - Helled, R.
A1  - Henri, P.
A1  - Hess, Sebastien
A1  - Hillier, J. K.
A1  - Hofstadter, M. H.
A1  - Holme, R.
A1  - Horanyi, M.
A1  - Hospodarsky, George B.
A1  - Hsu, S.
A1  - Irwin, P.
A1  - Jackman, C. M.
A1  - Karatekin, O.
A1  - Kempf, Sascha
A1  - Khalisi, E.
A1  - Konstantinidis, K.
A1  - Kruger, H.
A1  - Kurth, William S.
A1  - Labrianidis, C.
A1  - Lainey, V.
A1  - Lamy, L. L.
A1  - Laneuville, Matthieu
A1  - Lucchesi, D.
A1  - Luntzer, A.
A1  - MacArthur, J.
A1  - Maier, A.
A1  - Masters, A.
A1  - McKenna-Lawlor, S.
A1  - Melin, H.
A1  - Milillo, A.
A1  - Moragas-Klostermeyer, Georg
A1  - Morschhauser, Achim
A1  - Moses, J. I.
A1  - Mousis, O.
A1  - Nettelmann, N.
A1  - Neubauer, F. M.
A1  - Nordheim, T.
A1  - Noyelles, B.
A1  - Orton, G. S.
A1  - Owens, Mathew
A1  - Peron, R.
A1  - Plainaki, C.
A1  - Postberg, F.
A1  - Rambaux, N.
A1  - Retherford, K.
A1  - Reynaud, Serge
A1  - Roussos, E.
A1  - Russell, C. T.
A1  - Rymer, Am.
A1  - Sallantin, R.
A1  - Sanchez-Lavega, A.
A1  - Santolik, O.
A1  - Saur, J.
A1  - Sayanagi, Km.
A1  - Schenk, P.
A1  - Schubert, J.
A1  - Sergis, N.
A1  - Sittler, E. C.
A1  - Smith, A.
A1  - Spahn, Frank
A1  - Srama, Ralf
A1  - Stallard, T.
A1  - Sterken, V.
A1  - Sternovsky, Zoltan
A1  - Tiscareno, M.
A1  - Tobie, G.
A1  - Tosi, F.
A1  - Trieloff, M.
A1  - Turrini, D.
A1  - Turtle, E. P.
A1  - Vinatier, S.
A1  - Wilson, R.
A1  - Zarkat, P.
T1  - The science case for an orbital mission to Uranus: Exploring the origins and evolution of ice giant planets
JF  - Planetary and space science
N2  - Giant planets helped to shape the conditions we see in the Solar System today and they account for more than 99% of the mass of the Sun's planetary system. They can be subdivided into the Ice Giants (Uranus and Neptune) and the Gas Giants (Jupiter and Saturn), which differ from each other in a number of fundamental ways. Uranus, in particular is the most challenging to our understanding of planetary formation and evolution, with its large obliquity, low self-luminosity, highly asymmetrical internal field, and puzzling internal structure. Uranus also has a rich planetary system consisting of a system of inner natural satellites and complex ring system, five major natural icy satellites, a system of irregular moons with varied dynamical histories, and a highly asymmetrical magnetosphere. Voyager 2 is the only spacecraft to have explored Uranus, with a flyby in 1986, and no mission is currently planned to this enigmatic system. However, a mission to the uranian system would open a new window on the origin and evolution of the Solar System and would provide crucial information on a wide variety of physicochemical processes in our Solar System. These have clear implications for understanding exoplanetary systems. In this paper we describe the science case for an orbital mission to Uranus with an atmospheric entry probe to sample the composition and atmospheric physics in Uranus' atmosphere. The characteristics of such an orbiter and a strawman scientific payload are described and we discuss the technical challenges for such a mission. This paper is based on a white paper submitted to the European Space Agency's call for science themes for its large-class mission programme in 2013.
KW  - Uranus
KW  - Magnetosphere
KW  - Atmosphere
KW  - Natural satellites
KW  - Rings
KW  - Planetary interior
Y1  - 2014
U6  - https://doi.org/10.1016/j.pss.2014.08.009
SN  - 0032-0633
VL  - 104
SP  - 122
EP  - 140
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Jewitt, David
A1  - Weaver, Harold
A1  - Mutchler, Max
A1  - Larson, Stephen
A1  - Agarwal, Jessica
T1  - Hubble space telescope observations of main-belt comet (596) scheila
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - We present Hubble Space Telescope Observations of (596) Scheila during its recent dust outburst. The nucleus remained point-like with absolute magnitude H(V) = 8.85 +/- 0.02 in our data, equal to the pre-outburst value, with no secondary fragments of diameter >= 100m (for assumed albedos 0.04). We find a coma having a peak scattering cross section similar to 2.2x10(4) km(2), corresponding to a mass in micron-sized particles of similar to 4x10(7) kg. The particles are deflected by solar radiation pressure on projected spatial scales similar to 2x10(4) km, in the sunward direction, and swept from the vicinity of the nucleus on timescales of weeks. The coma fades by similar to 30% between observations on UT 2010 December 27 and 2011 January 4. The observed mass loss is inconsistent with an origin either by rotational instability of the nucleus or by electrostatic ejection of regolith charged by sunlight. Dust ejection could be caused by the sudden but unexplained exposure of buried ice. However, the data are most simply explained by the impact, at similar to 5 km s(-1), of a previously unknown asteroid similar to 35m in diameter.
KW  - comets: general
KW  - comets: individual ((596) Scheila)
KW  - minor planets, asteroids: general
Y1  - 2011
U6  - https://doi.org/10.1088/2041-8205/733/1/L4
SN  - 2041-8205
VL  - 733
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Marschall, Raphael
A1  - Skorov, Yuri
A1  - Zakharov, Vladimir
A1  - Rezac, Ladislav
A1  - Gerig, Selina-Barbara
A1  - Christou, Chariton
A1  - Dadzie, S. Kokou
A1  - Migliorini, Alessandra
A1  - Rinaldi, Giovanna
A1  - Agarwal, Jessica
A1  - Vincent, Jean-Baptiste
A1  - Kappel, David
T1  - Cometary comae-surface links the physics of gas and dust from the surface to a spacecraft
JF  - Space science reviews
N2  - A comet is a highly dynamic object, undergoing a permanent state of change. These changes have to be carefully classified and considered according to their intrinsic temporal and spatial scales. The Rosetta mission has, through its contiguous in-situ and remote sensing coverage of comet 67P/Churyumov-Gerasimenko (hereafter 67P) over the time span of August 2014 to September 2016, monitored the emergence, culmination, and winding down of the gas and dust comae. This provided an unprecedented data set and has spurred a large effort to connect in-situ and remote sensing measurements to the surface. In this review, we address our current understanding of cometary activity and the challenges involved when linking comae data to the surface. We give the current state of research by describing what we know about the physical processes involved from the surface to a few tens of kilometres above it with respect to the gas and dust emission from cometary nuclei. Further, we describe how complex multidimensional cometary gas and dust models have developed from the Halley encounter of 1986 to today. This includes the study of inhomogeneous outgassing and determination of the gas and dust production rates. Additionally, the different approaches used and results obtained to link coma data to the surface will be discussed. We discuss forward and inversion models and we describe the limitations of the respective approaches. The current literature suggests that there does not seem to be a single uniform process behind cometary activity. Rather, activity seems to be the consequence of a variety of erosion processes, including the sublimation of both water ice and more volatile material, but possibly also more exotic processes such as fracture and cliff erosion under thermal and mechanical stress, sub-surface heat storage, and a complex interplay of these processes. Seasons and the nucleus shape are key factors for the distribution and temporal evolution of activity and imply that the heliocentric evolution of activity can be highly individual for every comet, and generalisations can be misleading.
KW  - comets
KW  - coma
KW  - gas
KW  - dust
KW  - dynamics
KW  - modelling
KW  - inversion
Y1  - 2020
U6  - https://doi.org/10.1007/s11214-020-00744-0
SN  - 0038-6308
SN  - 1572-9672
VL  - 216
IS  - 8
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Srama, Ralf
A1  - Krueger, H.
A1  - Yamaguchi, T.
A1  - Stephan, T.
A1  - Burchell, M.
A1  - Kearsley, A. T.
A1  - Sterken, V.
A1  - Postberg, F.
A1  - Kempf, S.
A1  - Grün, Eberhard
A1  - Altobelli, Nicolas
A1  - Ehrenfreund, P.
A1  - Dikarev, V.
A1  - Horanyi, M.
A1  - Sternovsky, Zoltan
A1  - Carpenter, J. D.
A1  - Westphal, A.
A1  - Gainsforth, Z.
A1  - Krabbe, A.
A1  - Agarwal, Jessica
A1  - Yano, H.
A1  - Blum, J.
A1  - Henkel, H.
A1  - Hillier, J.
A1  - Hoppe, P.
A1  - Trieloff, M.
A1  - Hsu, S.
A1  - Mocker, A.
A1  - Fiege, K.
A1  - Green, S. F.
A1  - Bischoff, A.
A1  - Esposito, F.
A1  - Laufer, R.
A1  - Hyde, T. W.
A1  - Herdrich, G.
A1  - Fasoulas, S.
A1  - Jaeckel, A.
A1  - Jones, G.
A1  - Jenniskens, P.
A1  - Khalisi, E.
A1  - Moragas-Klostermeyer, Georg
A1  - Spahn, Frank
A1  - Keller, H. U.
A1  - Frisch, P.
A1  - Levasseur-Regourd, A. C.
A1  - Pailer, N.
A1  - Altwegg, K.
A1  - Engrand, C.
A1  - Auer, S.
A1  - Silen, J.
A1  - Sasaki, S.
A1  - Kobayashi, M.
A1  - Schmidt, J.
A1  - Kissel, J.
A1  - Marty, B.
A1  - Michel, P.
A1  - Palumbo, P.
A1  - Vaisberg, O.
A1  - Baggaley, J.
A1  - Rotundi, A.
A1  - Roeser, H. P.
T1  - SARIM PLUS-sample return of comet 67P/CG and of interstellar matter
JF  - EXPERIMENTAL ASTRONOMY
N2  - The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.
KW  - Interstellar dust
KW  - Cometary dust
KW  - Churyumov Gerasimenko
KW  - Interplanetary dust
KW  - IMF
KW  - Cosmic vision
KW  - Sample return
KW  - Dust collector
KW  - Mass spectrometry
Y1  - 2012
U6  - https://doi.org/10.1007/s10686-011-9285-7
SN  - 0922-6435
SN  - 1572-9508
VL  - 33
IS  - 2-3
SP  - 723
EP  - 751
PB  - SPRINGER
CY  - DORDRECHT
ER  -