TNOs are Cool: A Survey of the Transneptunian Region     

Thomas G. Müller  Emmanuel Lellouch  Hermann Böhnhardt  John Stansberry  Antonella Barucci  Jacques Crovisier  Audrey Delsanti  Alain Doressoundiram  Elisabetta Dotto  René Duffard  Sonia Fornasier  Olivier Groussin  Pedro J. Gutiérrez  Olivier Hainaut  Alan W. Harris  Paul Hartogh  Daniel Hestroffer  Jonathan Horner  Dave Jewitt  Mark Kidger  Csaba Kiss  Pedro Lacerda  Luisa Lara  Tanya Lim  Michael Mueller  Raphael Moreno  Jose-Luis Ortiz  Miriam Rengel  Pablo Santos-Sanz  Bruce Swinyard  Nicolas Thomas  Audrey Thirouin  David Trilling 《Earth, Moon, and Planets》2009,105(2-4):209-219

Over one thousand objects have so far been discovered orbiting beyond Neptune. These trans-Neptunian objects (TNOs) represent the primitive remnants of the planetesimal disk from which the planets formed and are perhaps analogous to the unseen dust parent-bodies in debris disks observed around other main-sequence stars. The dynamical and physical properties of these bodies provide unique and important constraints on formation and evolution models of the Solar System. While the dynamical architecture in this region (also known as the Kuiper Belt) is becoming relatively clear, the physical properties of the objects are still largely unexplored. In particular, fundamental parameters such as size, albedo, density and thermal properties are difficult to measure. Measurements of thermal emission, which peaks at far-IR wavelengths, offer the best means available to determine the physical properties. While Spitzer has provided some results, notably revealing a large albedo diversity in this population, the increased sensitivity of Herschel and its superior wavelength coverage should permit profound advances in the field. Within our accepted project we propose to perform radiometric measurements of 139 objects, including 25 known multiple systems. When combined with measurements of the dust population beyond Neptune (e.g. from the New Horizons mission to Pluto), our results will provide a benchmark for understanding the Solar debris disk, and extra-solar ones as well.  相似文献   

Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta     

Horst Uwe Keller  Sonia Fornasier  Stubbe F. Hviid  Jörg Knollenberg  Miriam Rengel  Gabriele Cremonese  Detlef Koschny  Ekkehard Kührt  Holger Sierks  Cesare Barbieri  Hans Rickman  Michael F. A'Hearn  Maria-Antonella Barucci  Vania da Deppo  Björn J.R. Davidsson  Stefano Debei  Fritz Gliem  José J. Lopez Moreno  Giampiero Naletto  Angel Sanz Andrés 《Icarus》2007,187(1):87-103

The OSIRIS cameras on the Rosetta spacecraft observed Comet 9P/Tempel 1 from 5 days before to 10 days after it was hit by the Deep Impact projectile. The Narrow Angle Camera (NAC) monitored the cometary dust in 5 different filters. The Wide Angle Camera (WAC) observed through filters sensitive to emissions from OH, CN, Na, and OI together with the associated continuum. Before and after the impact the comet showed regular variations in intensity. The period of the brightness changes is consistent with the rotation period of Tempel 1. The overall brightness of Tempel 1 decreased by about 10% during the OSIRIS observations. The analysis of the impact ejecta shows that no new permanent coma structures were created by the impact. Most of the material moved with . Much of it left the comet in the form of icy grains which sublimated and fragmented within the first hour after the impact. The light curve of the comet after the impact and the amount of material leaving the comet ( of water ice and a presumably larger amount of dust) suggest that the impact ejecta were quickly accelerated by collisions with gas molecules. Therefore, the motion of the bulk of the ejecta cannot be described by ballistic trajectories, and the validity of determinations of the density and tensile strength of the nucleus of Tempel 1 with models using ballistic ejection of particles is uncertain.  相似文献   

Water and related chemistry in the solar system. A guaranteed time key programme for Herschel     

P. Hartogh  E. Lellouch  M. Banaszkiewicz  E.A. Bergin  N. Biver  M.I. Blecka  D. Bockelée-Morvan  J. Cernicharo  G. Davis  P. Encrenaz  A. González  T. de Graauw  D. Hutsemékers  E. Jehin  M. Kidger  A. de Lange  D.C. Lis  J. Manfroid  R. Moreno  G. Orton  M. Rengel  M. Sánchez-Portal  S. Sidher  B. Swinyard  N. Thomas  B. Vandenbussche  C. Waelkens 《Planetary and Space Science》2009,57(13):1596-1606

“Water and related chemistry in the Solar System” is a Herschel Space Observatory Guaranteed-Time Key Programme. This project, approved by the European Space Agency, aims at determining the distribution, the evolution and the origin of water in Mars, the outer planets, Titan, Enceladus and the comets. It addresses the broad topic of water and its isotopologues in planetary and cometary atmospheres. The nature of cometary activity and the thermodynamics of cometary comae will be investigated by studying water excitation in a sample of comets. The D/H ratio, the key parameter for constraining the origin and evolution of Solar System species, will be measured for the first time in a Jupiter-family comet. A comparison with existing and new measurements of D/H in Oort-cloud comets will constrain the composition of pre-solar cometary grains and possibly the dynamics of the protosolar nebula. New measurements of D/H in giant planets, similarly constraining the composition of proto-planetary ices, will be obtained. The D/H and other isotopic ratios, diagnostic of Mars’ atmosphere evolution, will be accurately measured in H₂O and CO. The role of water vapor in Mars’ atmospheric chemistry will be studied by monitoring vertical profiles of H₂O and HDO and by searching for several other species (and CO and H₂O isotopes). A detailed study of the source of water in the upper atmosphere of the Giant Planets and Titan will be performed. By monitoring the water abundance, vertical profile, and input fluxes in the various objects, and when possible with the help of mapping observations, we will discriminate between the possible sources of water in the outer planets (interplanetary dust particles, cometary impacts, and local sources). In addition to these inter-connected objectives, serendipitous searches will enhance our knowledge of the composition of planetary and cometary atmospheres.  相似文献   

Phytoremediation of Cadmium‐Contaminated Soil by Two Jerusalem Artichoke (Helianthus tuberosus L.) Genotypes     

Zhenhua Zhang  Rengel Zed  Zhaopu Liu  Hongbo Shao 《洁净——土壤、空气、水》2013,41(2):202-209

Jerusalem artichoke (Helianthus tuberosus L.) can be used not just for bioethanol production, bur potentially also for soil phytoremediation via removal of heavy metal pollutants. An experiment was carried out to characterize the phytoextraction efficiency of two Jerusalem artichoke genotype (NY2 and NY5) in cadmium (Cd) contaminated soil. After 90 days of growth, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. The chlorophyll content and chlorophyll a fluorescence parameters were slightly higher when plants were grown in Cd‐contaminated versus control soil. It implies that this examined NY2 and NY5 can extract more Cd than some hyperaccumulators, indicating that NY2 and NY5 can be applied to clean up Cd‐contaminated soils. Compared with NY2, NY5 had higher phytoextraction potential due to more biomass and higher concentrations of Cd in tissues, and may therefore be the better candidates for phytoremediation in Cd‐contaminated soil.  相似文献   

Mesospheric vertical thermal structure and winds on Venus from HHSMT CO spectral-line observations     

Miriam Rengel  Paul Hartogh  Christopher Jarchow 《Planetary and Space Science》2008,56(10):1368-1384

We report vertical thermal structure and wind velocities in the Venusian mesosphere retrieved from carbon monoxide (¹²CO J=2-1 and ¹³CO J=2-1) spectral line observations obtained with the Heinrich Hertz Submillimeter Telescope (HHSMT). We observed the mesosphere of Venus from two days after the second Messenger flyby of Venus (on 5 June 2007 at 23:10 UTC) during five days. Day-to-day and day-to-night temperature variations and short-term fluctuations of the mesospheric zonal flow were evident in our data. The extensive layer of warm air detected recently by SPICAV at 90-100 km altitude is also detected in the temperature profiles reported here.These data were part of a coordinated ground-based Venus observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to contribute to a more thorough understanding of the global patterns of circulation of the Venusian atmosphere.  相似文献   

HHSMT observations of the Venusian mesospheric temperature, winds, and CO abundance around the MESSENGER flyby     

Miriam Rengel  Paul Hartogh  Christopher Jarchow 《Planetary and Space Science》2008,56(13):1688-1695

We present submillimeter observations of ¹²CO J=3-2 and 2-1, and ¹³CO J=2-1 lines of the Venusian mesosphere and lower thermosphere with the Heinrich Hertz Submillimeter Telescope (HHSMT) taken around the second MESSENGER flyby of Venus on 5 June 2007. The observations cover a range of Venus solar elongations with different fractional disk illuminations. Preliminary results like temperature and CO abundance profiles are presented.These data are part of a coordinated observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to contribute to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to a more thorough understanding of the global patters of circulation of the Venusian atmosphere.  相似文献