bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy ion irradiation of astrophysical ice analogs
Authors: Duarte Eduardo Seperuelo , Domaracka Alicja , Boduch Philippe , Rothard Hermann , Balanzat Emmanuel , Dartois Emmanuel , Pilling Sergio , Farenzena Lucio , da Silveira Enio Frota 
Published: April 2010

AbstractIcy grain mantles consist of small molecules containing hydrogen, carbon, oxygen and nitrogen atoms (e.g. H2O, CO, CO2, NH3). Such ices, present in different astrophysical environments (giant planets satellites, comets, dense clouds, and protoplanetary disks), are subjected to irradiation of different energetic particles: UV radiation, ion bombardment (solar and stellar wind as well as galactic cosmic rays), and secondary electrons due to cosmic ray ionization of H2. The interaction of these particles with astrophysical ice analogs has been the object of research over the last decades. However, there is a lack of information on the effects induced by the heavy ion component of cosmic rays in the electronic energy loss regime. The aim of the present work is to simulate of the astrophysical environment where ice mantles are exposed to the heavy ion cosmic ray irradiation.Sample ice films at 13K were irradiated by nickel ions with energies in the 1-10 MeV/u range and analyzed by means of FTIR spectrometry. Nickel ions were used because their energy deposition is similar to that deposited by iron ions, which are particularly abundant cosmic rays amongst the heaviest ones.In this work the effects caused by nickel ions on condensed gases are studied (destruction and production of molecules as well as associated cross sections, sputtering yields) and compared with respective values for light ions and UV photons.
Collision probabilities of migrating small bodies and dust particles with planets
Authors: Ipatov Sergei I. 
Published: April 2010

AbstractProbabilities of collisions of migrating small bodies and dust particles produced by these bodies with planets were studied. Various Jupiter-family comets, Halley-type comets, long-period comets, trans-Neptunian objects, and asteroids were considered. The total probability of collisions of any considered body or particle with all planets did not exceed 0.2. The amount of water delivered from outside of Jupiter's orbit to the Earth during the formation of the giant planets could exceed the amount of water in Earth's oceans. The ratio of the mass of water delivered to a planet by Jupiter-family comets or Halley-type comets to the mass of the planet can be greater for Mars, Venus, and Mercury, than that for Earth.
Simulations for Terrestrial Planets Formation
Authors: Ji Jianghui , Zhang Niu 
Published: April 2010

AbstractWe investigate the formation of terrestrial planets in the late stage of planetary formation using two-planet model. At that time, the protostar has formed for about 3 Myr and the gas disk has dissipated. In the model, the perturbations from Jupiter and Saturn are considered. We also consider variations of the mass of outer planet, and the initial eccentricities and inclinations of embryos and planetesimals. Our results show that, terrestrial planets are formed in 50 Myr, and the accretion rate is about 60% - 80%. In each simulation, 3 - 4 terrestrial planets are formed inside “Jupiter” with masses of 0.15 – 3.6 M⊕. In the 0.5 - 4AU, when the eccentricities of planetesimals are excited, planetesimals are able to accrete material from wide radial direction. The plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this mechanism. Accretion may also happen a few times between two giant planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 108 yr.
Galactic environment and cometary flux from the Oort cloud
Authors: Fouchard Marc 
Published: April 2010

AbstractThe Oort cloud, which corresponds to the furthest boundary of our Solar System, is considered as the main reservoir of long period comets. This cloud is likely a residual of the Solar System formation due to the gravitational effects of the young planets on the remaining planetesimals. Given that the cloud extends to large distances from the Sun (several times 10 000 AU), the bodies in this region have their trajectories affected by the Galactic environment of the Solar System. This environment is responsible for the re-injection of the Oort cloud comets into the planetary region of the Solar System. Such comets, also called “new comets”, are the best candidates to become Halley type or “old” long period comets under the influence of the planetary gravitational attractions. Consequently, the flux of new comets represents the first stage of the long trip from the Oort cloud to the observable populations of comets. This is why so many studies are still devoted to this flux.The different perturbers related to the Galactic environment of the Solar System, which have to be taken into account to explain the flux are reviewed. Special attention will be paid to the gravitational effects of stars passing close to the Sun and to the Galactic tides resulting from the difference of the gravitational attraction of the Galaxy on the Sun and on a comet. The synergy which takes place between these two perturbers is also described.
Influence of trans-neptunian objects on motion of major planets and limitation on the total TNO mass from planet and spacecraft ranging
Authors: Pitjeva E. V. 
Published: April 2010

AbstractPerturbations from asteroids and Trans-Neptunian Objects affect significantly on the orbits of planets and should be taken into account when high-accuracy planetary ephemerides are constructed. On the other hand, from an analysis of motion of the major planets by processing of precise measurements of spacecraft a limitation on the total TNO mass may be obtained. To estimate influence of TNO on motion of planets the largest 21 TNO have been included into the process of simultaneous numerical integration, and positions of planets obtained with taking for TNO have been compared with positions of planets of numerical EPM ephemeris of IAA RAS constructed without these objects. The perturbations of other TNO have been modeled by the perturbation from a circular ring having a radius 43 AU and different masses. It has been shown that all the test masses of the TNO ring except the minimum mass (5.26⋅10−8M⊙) are too large and make the data residuals worse. Thus, the upper limit of the total mass of all TNO including Pluto, the 21 largest TNO and the TNO ring (with the 43 AU radius) should not exceed 8.04⋅10−8M⊙.
Effect of the tensile strength on the stability against rotational breakup of icy bodies
Authors: Toth Imre , Lisse Carey M. 
Published: April 2010

AbstractFocusing on primitive icy minor bodies in the solar system like cometary nuclei, centaurs, transneptunian objects (TNOs), and main-belt comets (MBCs) we investigate the stability of these objects against rotational breakup by comparing their location in (radius – rotational period) space with respect to separation lines of the stable and breakup zones in this plane. We estimate the bulk tensile strength according to new structural and elasto-mechanical models of grain-aggregates, using these tensile strengths to compute separation lines. We note that the process of grain coagulation and growth is highly uncertain in the field of solar system formation and we simply don't know how to grow interstellar grains to aggregates larger than about 1 mm but we apply in our calculations the recently available elasto-mechanical models of grain-aggregates. Accorging to this study most of the observed comets, centaurs, TNOs, and MBCs are stable against rotational breakup, with a few notable exceptions. E.g., we suggest that the rotational fission is a likely scenario for the Haumea-family in the Kuiper belt.
Ground-based observations of Phoebe (S9) and its rotational dynamics
Authors: Aleshkina Ekaterina Yu. , Devyatkin Alexandr V. , Gorshanov Denis L. 
Published: April 2010

AbstractAnalysis of CCD observations of Phoebe, the 9th satellite of Saturn (visual magnitude of about 16.5), with a mirror astrograph ZA-320M at Pulkovo Observatory in Saint-Petersburg are presented. Photometric observations are performed both in the integral band of the telescope and in bands BVR of the Johnson system. Reference catalogues USNO-A2.0 (for R - filter and integral observations) and Ticho-2 (for V and B - filters) were used. Rotational light-curve data for Phoebe taken over a short time span (2 - 8 hours) for several nights are presented. Numerical investigation of the evolution of Phoebe's rotational dynamics is carried out. The probability of Phoebe's capture in resonant states that are distinct from 1:1 is estimated.
A cometary perspective of Enceladus
Authors: Boice Daniel C. , Goldstein Raymond 
Published: April 2010

AbstractIcy plumes venting from Enceladus draw obvious comparisons to such features seen in comets. This paper outlines a consistent evolution from cometary activity to larger icy bodies in the outer solar system. The major differences are due to the systematic effects of increased gravity, including more spherical solid bodies (self-gravity), less porosity, the possible existence of liquid water due to internal sources of heat (Enceladus) versus possible cometary cyrovolcanism, internal inhomogeneities leading to jet-like features, and the possibility of a quasi-bound dusty gas atmosphere, as opposed to the extensive exospheres of comets. Similarities exist also, including gas and dust emission and the filamentary nature of jet-like features (caused by surface topography in comets), surface evolution by dust accumulation, heat and gas transport through the surface layers, among others. Initial results regarding the plume chemistry and comparisons to CAPS ion data show similarities too. Others have considered additional effects such as, charging of particles, micrometeorite impacts and complex interactions with the E-ring neutrals and plasma in great detail so these topics remain outside the scope of this paper.
How do the small planetary satellites rotate?
Authors: Melnikov Alexander V. , Shevchenko Ivan I. 
Published: April 2010

AbstractWe investigate the problem of the typical rotation states of the small planetary satellites from the viewpoint of the dynamical stability of their rotation. We show that the majority of the discovered satellites with unknown rotation periods cannot rotate synchronously, because no stable synchronous 1:1 spin-orbit state exists for them. They rotate either much faster than synchronously (those tidally unevolved) or, what is much less probable, chaotically (tidally evolved objects or captured slow rotators).
Surface properties of icy transneptunian objects from the second ESO large program
Authors: DeMeo Francesca E. , Barucci Maria Antonietta , Alvarez-Candal Alvaro , de Bergh Catherine , Fornasier Sonia , Merlin Frédéric , Perna Davide , Belskaya Irina 
Published: April 2010

AbstractAn analysis is well underway for the data from the second Large Program (PI M. A. Barucci) dedicated to investigating the surface properties of Centaurs and Transneptunian objects through spectroscopic, photometric color, lightcurve, and polarimetric observations using the European Southern Observatory (ESO) Very Large Telescope (VLT) and New Technology Telescope (NTT). 45 objects were observed between 2006 and 2008, allowing a broad characterization of at least the largest and brightest objects among this population. In this report, we summarize all our findings, but focus on the analysis of the presence of ices such as methane, ethane, nitrogen, ammonia hydrate, methanol, and particularly H2O which is so abundant throughout the outer solar system.
The Dark Red Spot on KBO Haumea
Authors: Lacerda Pedro 
Published: April 2010

AbstractKuiper belt object 136108 Haumea is one of the most fascinating bodies in our solar system. Approximately 2000 × 1600 × 1000 km in size, it is one of the largest Kuiper belt objects (KBOs) and an unusually elongated one for its size. The shape of Haumea is the result of rotational deformation due to its extremely short 3.9-hour rotation period. Unlike other 1000 km-scale KBOs which are coated in methane ice the surface of Haumea is covered in almost pure H2O-ice. The bulk density of Haumea, estimated around 2.6 g cm−3, suggests a more rocky interior composition, different from the H2O-ice surface. Recently, Haumea has become the second KBO after Pluto to show observable signs of surface features. A region darker and redder than the average surface of Haumea has been identified, the composition and origin of which remain unknown. I discuss this recent finding and what it may tell us about Haumea.
Ground based observation of TNO targets for the Herschel Space Observatory
Authors: Duffard R. , Ortiz J. L. , Thirouin A. , Santos-Sanz P. , Morales N. 
Published: April 2010

AbstractWe have observed a subset of TNOs that are going to be studied by means of Herschel Space Telescope (HSO). More than 50 objects have been studied astrometrically and 30 with time series photometry. The main conclusion regarding the astrometry is that all the observed HSO targets have ephemerides uncertainties smaller than 5 arcsec, needed for the correct pointing of the space telescope. Concerning the time series analysis of the targets, most of the objects present low amplitude variability. This is an on-going program and more results are expected.
Dynamics, Origin, and Activation of Main Belt Comets
Authors: Haghighipour Nader 
Published: April 2010

AbstractThe discovery of Main Belt Comets (MBCs) has raised many questions regarding the origin and activation mechanism of these objects. Results of a study of the dynamics of these bodies suggest that MBCs were formed in-situ as the remnants of the break-up of large icy asteroids. Simulations show that similar to the asteroids in the main belt, MBCs with orbital eccentricities smaller than 0.2 and inclinations lower than 25° have stable orbits implying that many MBCs with initially larger eccentricities and inclinations might have been scattered to other regions of the asteroid belt. Among scattered MBCs, approximately 20% reach the region of terrestrial planets where they might have contributed to the accumulation of water on Earth. Simulations also show that collisions among MBCs and small objects could have played an important role in triggering the cometary activity of these bodies. Such collisions might have exposed sub-surface water ice which sublimated and created thin atmospheres and tails around MBCs. This paper discusses the results of numerical studies of the dynamics of MBCs and their implications for the origin of these objects. The results of a large numerical modeling of the collisions of m-sized bodies with km-sized asteroids in the outer part of the asteroid belt are also presented and the viability of the collision-triggering activation scenario is discussed.
Are the main belt comets, comets?
Authors: Licandro Javier , Campins Humberto 
Published: April 2010

AbstractWe present the visible spectrum of asteroid-comet transition object 133P/Elst-Pizarro (7968), the first member of the new population of objects called Main Belt Comets (Hsieh & Jewitt 2006). The spectrum was obtained with the 4.2m William Herschel Telescope at the “Roque de los Muchachos” observatory. The orbital elements of 133P place it within the Themis collisional family, but the observed cometary activity during it last 3 perihelion passages also suggest a possible origin in the trans-Neptunian belt or the Oort Cloud, the known sources of comets. We found a clear similarity between our spectrum of 133P and those of other members of the Themis family such as 62 Erato, and a strong contrast with those of cometary nuclei, such as 162P/Siding-Spring. This spectral comparison leads us to conclude that 133P is unlikely to have a cometary origin. This conclusion is strengthened by spectral similarities with activated near-Earth asteroid 3200 Phaethon, and suggest that there are activated asteroids in the near-Earth asteroid and main belt populations with similar surface properties.
Material properties of transition objects 3200 Phaethon and 2003 EH1
Authors: Borovička J. , Koten P. , Spurný P. , Čapek D. , Shrbený L. , Štork R. 
Published: April 2010

AbstractAsteroids 3200 Phaethon and 196256 (2003 EH1) are connected with two major meteoroid streams, Geminids and Quadrantids, respectively. We have modeled the observed light curves and decelerations of Geminid and Quadrantid meteors and studied their spectra. In both cases, we have found typical bulk densities of about 2600 kg m−3, much larger than in cometary meteoroids. Sodium was partially lost from Geminids and Quadrantids due to solar heating. The Quadrantid material was therefore not hidden deep inside the parent body 1500 years ago, when the perihelion was low enough for sodium loss to occur.
Cometary nature of the 1908 Tunguska cosmic body
Authors: Ibodov F. S. , Grigorian S. S. , Ibadov S. 
Published: April 2010

AbstractThe cometary nature of the 1908 Tunguska cosmic body is compatible with the predictions of an analytical theory of the 1908 Tunguska explosion developed in 1976–1979. The theory takes into account the three simultaneously occurring processes, namely aerodynamic destruction of the cosmic body in the Earth's atmosphere, transversal expansion of the crushed mass under the action of pressure gradient on the frontal surface of the body, and an aerodynamic deceleration of crushed expanding mass. The use, for the mechanical parameters of the Tunguska cosmic body, of the characteristics of a cometary nuclei such as that of comet Halley 1986 III and comet Shoemaker – Levy 9 1994, gives parameters of the Tunguska explosion derived from observations of Tunguska event in the Siberian taiga in 1908.
Observations of comets and minor planets at Kiev comets station (585)
Authors: Baransky Alexander R. , Churuymov Klim I. , Ponomarenko Vasyl A. 
Published: April 2010

AbstractWe present the results of astrometric and photometric observations of comets and minor planets obtained at the Kiev comet station (Code MPC 585) of the Astronomical Observatory of Kyiv Shevchenko National University in 2006-2009. The 2318 position observations of 176 comets, 302 observations of 57 numbered minor planets, and 220 observations of 30 unnumbered minor planets were obtained. The accuracy of the astrometric observations of the comets is analyzed.
Mass Cultivation of Chroococcus turgidus and Oscillatoria sp. and Effective Harvesting of Biomass by Low-cost methods
Authors: N Mohan , P Hanumantha Rao , R Ranjith Kumar , V Sivasubramanian 
Published: April 2010

AbstractThe potential of microalgal biomasses for the production of biochemicals such as pigments, vitamins, antibiotics, polysaccharides, proteins, essential fatty acids, bio-flocculants, enzymes, etc. is well known. The purpose of this study was to cultivate two cyanobacterial species namely Chroococcus turgidus and Oscillatoria sp., isolated from industrial effluents, using a suitable growth medium in a large-scale High Rate Algal (HRA) pond. The biomolecules such as total protein, total carbohydrate and total lipid, and the pigments chlorophyll, phycobilins, β-carotene, were analysed at regular intervals during cultivation. In addition, the total bacterial cell numbers were enumerated during the study and their influence on algal growth was studied. The algal biomass was harvested by low-cost methods such as auto-flocculation and auto-floatation.
Three-dimensional distribution of transient interactions in the nuclear pore complex obtained from single-molecule snapshots
Authors: Ma Jiong , Yang Weidong 
Published: April 2010

The translocation of large macromolecules through the nuclear pore complex (NPC) of eukaryotic cells is hindered by the phenylalanine-glycine (FG) nucleoporin (Nup) barrier unless molecules are chaperoned by transport receptors. The precise mechanism of facilitated translocation remains unclear due to the challenges of measuring the series of transient interactions between a transport receptor and the FG-Nups. This study developed single-point edge-excitation subdiffraction microscopy to obtain a three-dimensional density map of the transient interactions with a spatiotemporal resolution of 9 nm and 400 μs. Three unique features were observed under real-time trafficking conditions that have escaped detection by conventional electron microscopy: (
i
) the spatial density of interaction sites between Importin β1 (Imp β1, a major transport receptor) and the FG-Nups gradually increases from both sides of the NPC and is highest in the central pore region; (
ii
) cargo-free or cargo-bound Imp β1 rarely occupies an axial channel with a diameter of approximately 10–20 nm at its narrowest point through the NPC; and (
iii
) the pathway of facilitated translocation through the NPC depends more on the interaction sites of the FG-Nups than on the NPC architecture.
Electric power from offshore wind via synoptic-scale interconnection
Authors: Kempton Willett , Pimenta Felipe M. , Veron Dana E. , Colle Brian A. 
Published: April 2010

World wind power resources are abundant, but their utilization could be limited because wind fluctuates rather than providing steady power. We hypothesize that wind power output could be stabilized if wind generators were located in a meteorologically designed configuration and electrically connected. Based on 5 yr of wind data from 11 meteorological stations, distributed over a 2,500 km extent along the U.S. East Coast, power output for each hour at each site is calculated. Each individual wind power generation site exhibits the expected power ups and downs. But when we simulate a power line connecting them, called here the Atlantic Transmission Grid, the output from the entire set of generators rarely reaches either low or full power, and power changes slowly. Notably, during the 5-yr study period, the amount of power shifted up and down but never stopped. This finding is explained by examining in detail the high and low output periods, using reanalysis data to show the weather phenomena responsible for steady production and for the occasional periods of low power. We conclude with suggested institutions appropriate to create and manage the power system analyzed here.
High-resolution x-ray diffraction microscopy of specifically labeled yeast cells
Authors: Nelson Johanna , Huang Xiaojing , Steinbrener Jan , Shapiro David , Kirz Janos , Marchesini Stefano , Neiman Aaron M. , Turner Joshua J. , Jacobsen Chris 
Published: April 2010

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11–13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast
Saccharomyces cerevisiae
. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.