Bibliografías temáticas / Planetesimal

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Literatura académica sobre el tema "Planetesimal"

Autor: Grafiati
Publicado: 4 de junio de 2021
Última modificación: 16 de febrero de 2022

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Artículos de revistas sobre el tema "Planetesimal"

1

Voelkel, Oliver, Hubert Klahr, Christoph Mordasini, Alexandre Emsenhuber y Christian Lenz. "Effect of pebble flux-regulated planetesimal formation on giant planet formation". Astronomy & Astrophysics 642 (octubre de 2020): A75. http://dx.doi.org/10.1051/0004-6361/202038085.

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Context. The formation of gas giant planets by the accretion of 100 km diameter planetesimals is often thought to be inefficient. A diameter of this size is typical for planetesimals and results from self-gravity. Many models therefore use small kilometer-sized planetesimals, or invoke the accretion of pebbles. Furthermore, models based on planetesimal accretion often use the ad hoc assumption of planetesimals that are distributed radially in a minimum-mass solar-nebula way. Aims. We use a dynamical model for planetesimal formation to investigate the effect of various initial radial density distributions on the resulting planet population. In doing so, we highlight the directive role of the early stages of dust evolution into pebbles and planetesimals in the circumstellar disk on the subsequent planet formation. Methods. We implemented a two-population model for solid evolution and a pebble flux-regulated model for planetesimal formation in our global model for planet population synthesis. This framework was used to study the global effect of planetesimal formation on planet formation. As reference, we compared our dynamically formed planetesimal surface densities with ad hoc set distributions of different radial density slopes of planetesimals. Results. Even though required, it is not the total planetesimal disk mass alone, but the planetesimal surface density slope and subsequently the formation mechanism of planetesimals that enables planetary growth through planetesimal accretion. Highly condensed regions of only 100 km sized planetesimals in the inner regions of circumstellar disks can lead to gas giant growth. Conclusions. Pebble flux-regulated planetesimal formation strongly boosts planet formation even when the planetesimals to be accreted are 100 km in size because it is a highly effective mechanism for creating a steep planetesimal density profile. We find that this leads to the formation of giant planets inside 1 au already by pure 100 km planetesimal accretion. Eventually, adding pebble accretion regulated by pebble flux and planetesimal-based embryo formation as well will further complement this picture.
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2

San Sebastián, I. L., O. M. Guilera y M. G. Parisi. "Planetesimal fragmentation and giant planet formation". Astronomy & Astrophysics 625 (mayo de 2019): A138. http://dx.doi.org/10.1051/0004-6361/201834168.

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Context. Most planet formation models that incorporate planetesimal fragmentation consider a catastrophic impact energy threshold for basalts at a constant velocity of 3 km s−1 throughout the process of the formation of the planets. However, as planets grow, the relative velocities of the surrounding planetesimals increase from velocities of the order of meters per second to a few kilometers per second. In addition, beyond the ice line where giant planets are formed, planetesimals are expected to be composed roughly of 50% ices. Aims. We aim to study the role of planetesimal fragmentation on giant planet formation considering the planetesimal catastrophic impact energy threshold as a function of the planetesimal relative velocities and compositions. Methods. We improved our model of planetesimal fragmentation incorporating a functional form of the catastrophic impact energy threshold with the planetesimal relative velocities and compositions. We also improved in our model the accretion of small fragments produced by the fragmentation of planetesimals during the collisional cascade considering specific pebble accretion rates. Results. We find that a more accurate and realistic model for the calculation of the catastrophic impact energy threshold tends to slow down the formation of massive cores. Only for reduced grain opacity values at the envelope of the planet is the cross-over mass achieved before the disk timescale dissipation. Conclusions. While planetesimal fragmentation favors the quick formation of massive cores of 5–10 M⊕ the cross-over mass could be inhibited by planetesimal fragmentation. However, grain opacity reduction or pollution by the accreted planetesimals together with planetesimal fragmentation could explain the formation of giant planets with low-mass cores.
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3

Gerbig, Konstantin, Christian T. Lenz y Hubert Klahr. "Linking planetesimal and dust content in protoplanetary disks via a local toy model". Astronomy & Astrophysics 629 (septiembre de 2019): A116. http://dx.doi.org/10.1051/0004-6361/201935278.

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Context. If planetesimal formation is an efficient process, as suggested by several models involving gravitational collapse of pebble clouds, then, not before long, a significant part of the primordial dust mass should be absorbed in many km-sized objects. A good understanding of the total amount of solids in the disk around a young star is crucial for planet formation theory. However, as the mass of particles above the mm size cannot be assessed observationally, one must ask how much mass is hidden in bigger objects. Aims. We performed 0-d local simulations to study how the planetesimal to dust and pebble ratio evolves in time and to develop an understanding of the potentially existing mass in planetesimals for a certain amount of dust and pebbles at a given disk age. Methods. We performed a parameter study based on a model considering dust growth, planetesimal formation, and collisional fragmentation of planetesimals, while neglecting radial transport processes. Results. While at early times, dust is the dominant solid particle species, there is a phase during which planetesimals make up a significant portion of the total mass starting at approximately 104–106 yr. The time of this phase and the maximal total planetesimal mass strongly depend on the distance to the star R, the initial disk mass, and the efficiency of planetesimal formation ɛ. Planetesimal collisions are more significant in more massive disks, leading to lower relative planetesimal fractions compared to less massive disks. After approximately 106 yr, our model predicts planetesimal collisions to dominate, which resupplies small particles. Conclusions. In our model, planetesimals form fast and everywhere in the disk. For a given ɛ, we are able to relate the dust content and mass of a given disk to its planetesimal content, providing us with some helpful basic intuition about mass distribution of solids and its dependence on underlying physical processes.
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Coleman, Gavin A. L. "From dust to planets – I. Planetesimal and embryo formation". Monthly Notices of the Royal Astronomical Society 506, n.º 3 (6 de julio de 2021): 3596–614. http://dx.doi.org/10.1093/mnras/stab1904.

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ABSTRACT Planet formation models begin with proto-embryos and planetesimals already fully formed, missing out a crucial step, the formation of planetesimals/proto-embryos. In this work, we include prescriptions for planetesimal and proto-embryo formation arising from pebbles becoming trapped in short-lived pressure bumps, in thermally evolving viscous discs to examine the sizes and distributions of proto-embryos and planetesimals throughout the disc. We find that planetesimal sizes increase with orbital distance, from ∼10 km close to the star to hundreds of kilometres further away. Proto-embryo masses are also found to increase with orbital radius, ranging from $10^{-6}{\, {\rm M}_{\oplus }}$ around the iceline, to $10^{-3}{\, {\rm M}_{\oplus }}$ near the orbit of Pluto. We include prescriptions for pebble and planetesimal accretion to examine the masses that proto-embryos can attain. Close to the star, planetesimal accretion is efficient due to small planetesimals, whilst pebble accretion is efficient where pebble sizes are fragmentation limited, but inefficient when drift dominated due to low accretion rates before the pebble supply diminishes. Exterior to the iceline, planetesimal accretion becomes inefficient due to increasing planetesimal eccentricities, whilst pebble accretion becomes more efficient as the initial proto-embryo masses increase, allowing them to significantly grow before the pebble supply is depleted. Combining both scenarios allows for more massive proto-embryos at larger distances, since the accretion of planetesimals allows pebble accretion to become more efficient, allowing giant planet cores to form at distances upto $10{\, {\rm au}}$. By including more realistic initial proto-embryo and planetesimal sizes, as well as combined accretion scenarios, should allow for a more complete understanding in the beginning to end process of how planets and planetary systems form.
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5

Schaffer, Noemi, Anders Johansen, Lukas Cedenblad, Bernhard Mehling y Dhrubaditya Mitra. "Erosion of planetesimals by gas flow". Astronomy & Astrophysics 639 (julio de 2020): A39. http://dx.doi.org/10.1051/0004-6361/201935763.

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The first stages of planet formation take place in protoplanetary disks that are largely made up of gas. Understanding how the gas affects planetesimals in the protoplanetary disk is therefore essential. In this paper, we discuss whether or not gas flow can erode planetesimals. We estimated how much shear stress is exerted onto the planetesimal surface by the gas as a function of disk and planetesimal properties. To determine whether erosion can take place, we compared this with previous measurements of the critical stress that a pebble-pile planetesimal can withstand before erosion begins. If erosion took place, we estimated the erosion time of the affected planetesimals. We also illustrated our estimates with two-dimensional numerical simulations of flows around planetesimals using the lattice Boltzmann method. We find that the wall shear stress can overcome the critical stress of planetesimals in an eccentric orbit within the innermost regions of the disk. The high eccentricities needed to reach erosive stresses could be the result of shepherding by migrating planets. We also find that if a planetesimal erodes, it does so on short timescales. For planetesimals residing outside of 1 au, we find that they are mainly safe from erosion, even in the case of highly eccentric orbits.
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6

Liu, Beibei, Chris W. Ormel y Anders Johansen. "Growth after the streaming instability". Astronomy & Astrophysics 624 (abril de 2019): A114. http://dx.doi.org/10.1051/0004-6361/201834174.

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Context. Streaming instability is a key mechanism in planet formation, clustering pebbles into planetesimals with the help of self-gravity. It is triggered at a particular disk location where the local volume density of solids exceeds that of the gas. After their formation, planetesimals can grow into protoplanets by feeding from other planetesimals in the birth ring as well as by accreting inwardly drifting pebbles from the outer disk. Aims. We aim to investigate the growth of planetesimals into protoplanets at a single location through streaming instability. For a solar-mass star, we test the conditions under which super-Earths are able to form within the lifetime of the gaseous disk. Methods. We modified the Mercury N-body code to trace the growth and dynamical evolution of a swarm of planetesimals at a distance of 2.7 AU from the star. The code simulates gravitational interactions and collisions among planetesimals, gas drag, type I torque, and pebble accretion. Three distributions of planetesimal sizes were investigated: (i) a mono-dispersed population of 400 km radius planetesimals, (ii) a poly-dispersed population of planetesimals from 200 km up to 1000 km, (iii) a bimodal distribution with a single runaway body and a swarm of smaller, 100 km size planetesimals. Results. The mono-dispersed population of 400 km size planetesimals cannot form protoplanets of a mass greater than that of the Earth. Their eccentricities and inclinations are quickly excited, which suppresses both planetesimal accretion and pebble accretion. Planets can form from the poly-dispersed and bimodal distributions. In these circumstances, it is the two-component nature that damps the random velocity of the large embryo through the dynamical friction of small planetesimals, allowing the embryo to accrete pebbles efficiently when it approaches 10−2 M⊕. Accounting for migration, close-in super-Earth planets form. Super-Earth planets are likely to form when the pebble mass flux is higher, the disk turbulence is lower, or the Stokes number of the pebbles is higher. Conclusions. For the single site planetesimal formation scenario, a two-component mass distribution with a large embryo and small planetesimals promotes planet growth, first by planetesimal accretion and then by pebble accretion of the most massive protoplanet. Planetesimal formation at single locations such as ice lines naturally leads to super-Earth planets by the combined mechanisms of planetesimal accretion and pebble accretion.
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Johansen, Anders y Bertram Bitsch. "Exploring the conditions for forming cold gas giants through planetesimal accretion". Astronomy & Astrophysics 631 (23 de octubre de 2019): A70. http://dx.doi.org/10.1051/0004-6361/201936351.

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The formation of cold gas giants similar to Jupiter and Saturn in orbit and mass is a great challenge for planetesimal-driven core accretion models because the core growth rates far from the star are low. Here we model the growth and migration of single protoplanets that accrete planetesimals and gas. We integrated the core growth rate using fits in the literature to N-body simulations, which provide the efficiency of accreting the planetesimals that a protoplanet migrates through. We take into account three constraints from the solar system and from protoplanetary discs: (1) the masses of the terrestrial planets and the comet reservoirs in Neptune’s scattered disc and the Oort cloud are consistent with a primordial planetesimal population of a few Earth masses per AU, (2) evidence from the asteroid belt and the Kuiper belt indicates that the characteristic planetesimal diameter is 100 km, and (3) observations of protoplanetary discs indicate that the dust is stirred by weak turbulence; this gas turbulence also excites the inclinations of planetesimals. Our nominal model built on these constraints results in maximum protoplanet masses of 0.1 Earth masses. Ignoring constraint (1) above, we show that even a planetesimal population of 1000 Earth masses, corresponding to 50 Earth masses per AU, fails to produce cold gas giants (although it successfully forms hot and warm gas giants). We conclude that a massive planetesimal reservoir is in itself insufficient to produce cold gas giants. The formation of cold gas giants by planetesimal accretion additionally requires that planetesimals are small and that the turbulent stirring is very weak, thereby violating all three above constraints.
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Shibata, Sho, Ravit Helled y Masahiro Ikoma. "The origin of the high metallicity of close-in giant exoplanets". Astronomy & Astrophysics 633 (enero de 2020): A33. http://dx.doi.org/10.1051/0004-6361/201936700.

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Context. Recent studies suggest that in comparison to their host star, many giant exoplanets are highly enriched with heavy elements and can contain several tens of Earth masses of heavy elements or more. Such enrichment is considered to have been delivered by the accretion of planetesimals in late formation stages. Previous dynamical simulations, however, have shown that planets cannot accrete such high masses of heavy elements through “in situ” planetesimal accretion. Aims. We investigate whether a giant planet migrating inward can capture planetesimals efficiently enough to significantly increase its metallicity. Methods. We performed orbital integrations of a migrating giant planet and planetesimals in a protoplanetary gas disc to infer the planetesimal mass that is accreted by the planet. Results. We find that the two shepherding processes of mean motion resonance trapping and aerodynamic gas drag inhibit the planetesimal capture of a migrating planet. However, the amplified libration allows the highly-excited planetesimals in the resonances to escape from the resonance trap and to be accreted by the planet. Consequently, we show that a migrating giant planet captures planetesimals with total mass of several tens of Earth masses if the planet forms at a few tens of AU in a relatively massive disc. We also find that planetesimal capture occurs efficiently in a limited range of semi-major axis and that the total captured planetesimal mass increases with increasing migration distances. Our results have important implications for understanding the relation between giant planet metallicity and mass, as we suggest that it reflects the formation location of the planet – or more precisely, the location where runaway gas accretion occurred. We also suggest the observed metal-rich close-in Jupiters migrated to their present locations from afar, where they had initially formed.
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9

Wallace, Spencer C. y Thomas R. Quinn. "N-body simulations of terrestrial planet growth with resonant dynamical friction". Monthly Notices of the Royal Astronomical Society 489, n.º 2 (19 de agosto de 2019): 2159–76. http://dx.doi.org/10.1093/mnras/stz2284.

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ABSTRACT We investigate planetesimal accretion via a direct N-body simulation of an annulus at 1 au orbiting a 1 M$\odot$ star. The planetesimal ring, which initially contains N = 106 bodies is evolved into the oligarchic growth phase. Unlike previous lower resolution studies, we find that the mass distribution of planetesimals develops a bump at intermediate mass after the oligarchs form. This feature marks a boundary between growth modes. The smallest planetesimals are packed tightly enough together to populate mean motion resonances with the oligarchs, which heats the small bodies, enhancing their growth. If we depopulate most of the resonances by decreasing the width of the annulus, this effect becomes weaker. To clearly demonstrate the dynamics driving these growth modes, we also examine the evolution of a planetary embryo embedded in an annulus of collisionless planetesimals. In this case, we find that the resonances push planetesimals away from the embryo, decreasing the surface density of the bodies adjacent to the embryo. This effect only occurs when the annulus is wide enough and the mass resolution of the planetesimals is fine enough to populate the resonances. The bump we observe in the mass distribution resembles the 100 km power-law break seen in the size distribution of asteroid belt objects. Although the bump produced in our simulations occurs at a size larger than 100 km, we show that the bump location is sensitive to the initial planetesimal mass, which implies that this feature is potentially useful for constraining planetesimal formation models.
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Guilera, Octavio Miguel, Zsolt Sándor, María Paula Ronco, Julia Venturini y Marcelo Miguel Miller Bertolami. "Giant planet formation at the pressure maxima of protoplanetary disks". Astronomy & Astrophysics 642 (octubre de 2020): A140. http://dx.doi.org/10.1051/0004-6361/202038458.

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Context. Recent high-resolution observations of protoplanetary disks have revealed ring-like structures that can be associated to pressure maxima. Pressure maxima are known to be dust collectors and planet migration traps. The great majority of planet formation studies are based either on the pebble accretion model or on the planetesimal accretion model. However, recent studies proposed hybrid accretion of pebbles and planetesimals as a possible formation mechanism for Jupiter. Aims. We aim to study the full process of planet formation consisting of dust evolution, planetesimal formation, and planet growth at a pressure maximum in a protoplanetary disk. Methods. We compute, through numerical simulations, the gas and dust evolution in a protoplanetary disk, including dust growth, fragmentation, radial drift, and particle accumulation at a pressure maximum. The pressure maximum appears due to an assumed viscosity transition at the water ice line. We also consider the formation of planetesimals by streaming instability and the formation of a moon-size embryo that grows into a giant planet by the hybrid accretion of pebbles and planetesimals, all within the pressure maximum. Results. We find that the pressure maximum is an efficient collector of dust drifting inwards. The condition of planetesimal formation by streaming instability is fulfilled due to the large amount of dust accumulated at the pressure bump. Subsequently, a massive core is quickly formed (in ~104 yr) by the accretion of pebbles. After the pebble isolation mass is reached, the growth of the core slowly continues by the accretion of planetesimals. The energy released by planetesimal accretion delays the onset of runaway gas accretion, allowing a gas giant to form after ~1 Myr of disk evolution. The pressure maximum also acts as a migration trap. Conclusions. Pressure maxima generated by a viscosity transition at the water ice line are preferential locations for dust traps, planetesimal formation by streaming instability, and planet migration traps. All these conditions allow the fast formation of a giant planet by the hybrid accretion of pebbles and planetesimals.
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Tesis sobre el tema "Planetesimal"

1

Richardson, Derek C. "Planetesimal dynamics". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309052.

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Barnes, Rory. "The dynamics of the initial planetesimal disk /". Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5439.

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Armitage, Philip J., Josh A. Eisner y Jacob B. Simon. "PROMPT PLANETESIMAL FORMATION BEYOND THE SNOW LINE". IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621505.

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We develop a simple model to predict the radial distribution of planetesimal formation. The model is based on the observed growth of dust to millimeter-sized particles, which drift radially, pile-up, and form planetesimals where the stopping time and dust-to-gas ratio intersect the allowed region for streaming instability-induced gravitational collapse. Using an approximate analytic treatment, we first show that drifting particles define a track in metallicity-stopping time space whose only substantial dependence is on the disk's angular momentum transport efficiency. Prompt planetesimal formation is feasible for high particle accretion rates (relative to the gas, (M) over dot(p)/(M) over dot greater than or similar to 3 x 10(-2) for alpha = 10(-2)), which could only be sustained for a limited period of time. If it is possible, it would lead to the deposition of a broad and massive belt of planetesimals with a sharp outer edge. Numerically including turbulent diffusion and vapor condensation processes, we find that a modest enhancement of solids near the snow line occurs for centimeter-sized particles, but that this is largely immaterial for planetesimal formation. We note that radial drift couples planetesimal formation across radii in the disk, and suggest that considerations of planetesimal formation favor a model in which the initial deposition of material for giant planet cores occurs well beyond the snow line.
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Leinhardt, Zoë Malka. "Planetesimal evolution and the formation of terrestrial planets". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2359.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Astronomy. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Michikoshi, Shugo. "Theoretical study on planetesimal formation through gravitational instability". 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136768.

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Hughes, Anna. "Planetesimal growth through the accretion of small solids". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58965.

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The growth and migration of planetesimals in a young protoplanetary disk is fundamental to the planet formation process. However, in our modeling of early growth, there are a several processes that can inhibit smaller grains from growing to larger sizes, making growth beyond size scales of centimeters difficult. The observational data which are available ( e.g., relics from asteroids in our own solar system as well as gas lifetimes in other systems) suggest that early growth must be rapid. If a small number of 100-km-sized planetesimals do manage to form by some method such as streaming instability, then gas drag effects would enable such a body to efficiently accrete smaller solids from beyond its Hill sphere. This enhanced accretion cross-section, paired with dense gas and large populations of small solids enables a planet to grow at much faster rates. As the planetesimals accrete pebbles, they experience an additional angular momentum exchange, which could cause slow inward drift and a consequent back-reaction on growth rates. We present self-consistent hydrodynamic simulations with direct particle integration and gas-drag coupling to estimate the rate of planetesimal growth due to pebble accretion. We explore a range of particle sizes and disk conditions using a wind tunnel simulation. We also perform numerical analyses of planetesimal growth and drift rates for a range of distances from the star. The results of our models indicate that rapid growth of planeteismals under our assumed model must be at orbital distances inwards of 1 AU, and that at such distances centimeter-sized pebbles and larger are required for maximized accretion. We find that growth beyond 1 AU is possible under certain limited, optimized conditions.
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Davison, Thomas M. "Numerical modelling of heat generation in porous planetesimal collisions". Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6333.

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An important unanswered question in planetary science is how planetesimals, the ~1–100 km solid precursors to asteroids and planets, were heated in the early Solar System. This thesis quantifies one possible heat source: planetesimal collisions. Recent work has predicted that collision velocities and planetesimal porosities were likely to have been higher than previously thought; this is likely to have significant implications on collision heating. The approach adopted in this research was to numerically model shock heating during planetesimal collisions. Simulations showed that an increase in porosity can significantly increase heating: in a 5 km s-1 collision between equal sized, non-porous planetesimals, no material was heated to the solidus, compared to two thirds of the mass of 50% porous planetesimals. Velocity also strongly influences heating: at 4 km s-1, an eighth of the mass of 50% porous planetesimals was heated to the solidus, compared to the entire mass at 6 km s-1. Further simulations quantified the influence on heating of the impactor-to-target mass ratio, the initial planetesimal temperature and the impact angle. A Monte Carlo model was developed to examine the cumulative heating caused by a population of impactors striking a parent body. In the majority of collisions the impactor was much smaller than the parent body, and only minor heating was possible. However, some larger or faster impactors were capable of causing significant heating without disrupting the parent body; these collisions could have heated up to 10% of the parent body to the solidus. To cause global heating, the collision must have catastrophically disrupted the parent body. The increase in specific internal energy from collisions was compared with the decay of short-lived radionuclides. In the first ~6 Ma, radioactive decay was the most important heat source. After ~10 Ma, the energy caused by collisions was likely to have overtaken radioactive decay as the dominant source.
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Simon, Jacob B., Philip J. Armitage, Andrew N. Youdin y Rixin Li. "Evidence for Universality in the Initial Planetesimal Mass Function". IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626045.

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Planetesimals may form from the gravitational collapse of dense particle clumps initiated by the streaming instability. We use simulations of aerodynamically coupled gas-particle mixtures to investigate whether the properties of planetesimals formed in this way depend upon the sizes of the particles that participate in the instability. Based on three high-resolution simulations that span a range of dimensionless stopping times 6 X 10(-3) <= tau <= 2, no statistically significant differences in the initial planetesimal mass function are found. The mass functions are fit by a power law, dN/dM(p) proportional to M-p(-p), with p = 1.5-1.7 and errors of Delta p approximate to 0.1. Comparing the particle density fields prior to collapse, we find that the high-wavenumber power spectra are similarly indistinguishable, though the large-scale geometry of structures induced via the streaming instability is significantly different between all three cases. We interpret the results as evidence for a near-universal slope to the mass function, arising from the small-scale structure of streaming-induced turbulence.
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9

Windmark, Fredrik [Verfasser] y Cornelis P. [Akademischer Betreuer] Dullemond. "Planetesimal formation by dust coagulation / Fredrik Windmark ; Betreuer: Cornelis P. Dullemond". Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177382938/34.

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Dittrich, Karsten [Verfasser] y Hubert [Akademischer Betreuer] Klahr. "Numerical Simulations of Planetesimal Formation in Protoplanetary Disks / Karsten Dittrich ; Betreuer: Hubert Klahr". Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177382873/34.

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Libros sobre el tema "Planetesimal"

1

Elkins-Tanton, Linda T. y Benjamin P. Weiss, eds. Planetesimals. Cambridge: Cambridge University Press, 2017. http://dx.doi.org/10.1017/9781316339794.

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P, Cruikshank Dale y United States. National Aeronautics and Space Administration., eds. The composition of planetesimal 5145 Pholus. [Washington, D.C: National Aeronautics and Space Administration, 1996.

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Murdock, Matthew J. Modelling planetesimal interactions during mid-stage evolution of the protoplanetary cloud. 1995.

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4

Garzon, F. Disks, Planetesimals and Planets. Astronomical Society of the Pacific, 2000.

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5

Elkins-Tanton, Linda T. y Benjamin P. Weiss. Planetesimals: Early Differentiation and Consequences for Planets. Cambridge University Press, 2017.

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E, Kress M., Tielens, A. G. G. M., Pendleton Yvonne J y Ames Research Center, eds. From Stardust to Planetesimals: Proceedings of a symposium held in Santa Clara, California, June 24-26, 1996. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1996.

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7

Trieloff, Mario. Noble Gases. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190647926.013.30.

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This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article.Although the second most abundant element in the cosmos is helium, noble gases are also called rare gases. The reason is that they are not abundant on terrestrial planets like our Earth, which is characterized by orders of magnitude depletion of—particularly light—noble gases when compared to the cosmic element abundance pattern. Indeed, such geochemical depletion and enrichment processes make noble gases so versatile concerning planetary formation and evolution: When our solar system formed, the first small grains started to adsorb small amounts of noble gases from the protosolar nebula, resulting in depletion of light He and Ne when compared to heavy noble gases Ar, Kr, and Xe: the so-called planetary type abundance pattern. Subsequent flash heating of the first small mm to cm-sized objects (chondrules and calcium, aluminum rich inclusions) resulted in further depletion, as well as heating—and occasionally differentiation—on small planetesimals, which were precursors of larger planets and which we still find in the asteroid belt today from where we get rocky fragments in form of meteorites. In most primitive meteorites, we even can find tiny rare grains that are older than our solar system and condensed billions of years ago in circumstellar atmospheres of, for example, red giant stars. These grains are characterized by nucleosynthetic anomalies and particularly identified by noble gases, for example, so-called s-process xenon.While planetesimals acquired a depleted noble gas component strongly fractionated in favor of heavy noble gases, the sun and also gas giants like Jupiter attracted a much larger amount of gas from the protosolar nebula by gravitational capture. This resulted in a cosmic or “solar type” abundance pattern, containing the full complement of light noble gases. Contrary to Jupiter or the sun, terrestrial planets accreted from planetesimals with only minor contributions from the protosolar nebula, which explains their high degree of depletion and basically “planetary” elemental abundance pattern. Indeed this depletion enables another tool to be applied in noble gas geo- and cosmochemistry: ingrowth of radiogenic nuclides. Due to heavy depletion of primordial nuclides like 36Ar and 130Xe, radiogenic ingrowth of 40Ar by 40K decay, 129Xe by 129I decay, or fission Xe from 238U or 244Pu decay are precisely measurable, and allow insight in the chronology of fractionation of lithophile parent nuclides and atmophile noble gas daughters, mainly caused by mantle degassing and formation of the atmosphere.Already the dominance of 40Ar in the terrestrial atmosphere allowed C. F v. Weizsäcker to conclude that most of the terrestrial atmosphere originated by degassing of the solid Earth, which is an ongoing process today at mid ocean ridges, where primordial helium leaves the lithosphere for the first time. Mantle degassing was much more massive in the past; in fact, most of the terrestrial atmosphere formed during the first 100 million years of Earth´s history, and was completed at about the same time when the terrestrial core formed and accretion was terminated by a giant impact that also formed our moon. However, before that time, somehow also tiny amounts of solar noble gases managed to find their way into the mantle, presumably by solar wind irradiation of small planetesimals or dust accreting to Earth. While the moon-forming impact likely dissipated the primordial atmosphere, today´s atmosphere originated by mantle degassing and a late veneer with asteroidal and possibly cometary contributions. As other atmophile elements behave similar to noble gases, they also trace the origin of major volatiles on Earth, for example, water, nitrogen, sulfur, and carbon.
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E, Kress M., Tielens, A. G. G. M., Pendleton Yvonne J, Ames Research Center y Astronomical Society of the Pacific. Meeting, eds. From Stardust to Planetesimals: Contributed papers : proceedings of a symposium held in Santa Clara, California, June 24-26, 1996. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1996.

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F, Garzón, ed. Disks, planetesimals, and planets: Proceedings of a Euroconference held at Puerto de la Cruz, Tenerife, Spain, 24-28 January 2000. San Francisco, Calif: Astronomical Society of the Pacific, 2000.

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From stardust to planetesimals: Symposium held as part of the 108th Annual Meeting of the Astronomical Society of the Pacific held at Santa Clara, California, 24-26 June 1996. San Francisco, Calif: Astronomical Society of the Pacific, 1997.

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Capítulos de libros sobre el tema "Planetesimal"

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Durran, Richard y Aubrey Truman. "Planetesimal diffusions". En Lecture Notes in Mathematics, 76–88. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/bfb0077917.

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Weiss, Benjamin P., Jérôme Gattacceca, Sabine Stanley, Pierre Rochette y Ulrich R. Christensen. "Paleomagnetic Records of Meteorites and Early Planetesimal Differentiation". En Planetary Magnetism, 341–90. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-5901-0_11.

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Geretshauser, R. J., R. Speith y W. Kley. "Simulation of Pre-planetesimal Collisions with Smoothed Particle Hydrodynamics". En High Performance Computing in Science and Engineering '11, 29–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-23869-7_3.

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Geretshauser, R. J., F. Meru, K. Schaal, R. Speith y W. Kley. "Simulation of Pre-planetesimal Collisions with Smoothed Particle Hydrodynamics II". En High Performance Computing in Science and Engineering ‘12, 51–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-33374-3_6.

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Sasaki, Sho. "Off-Disk Implantation of Early Solar Wind into a Planetesimal-Dust Cloud". En Origin and Evolution of Interplanetary Dust, 425–28. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3640-2_87.

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Klahr, Hubert, Thomas Pfeil y Andreas Schreiber. "Instabilities and Flow Structures in Protoplanetary Disks: Setting the Stage for Planetesimal Formation". En Handbook of Exoplanets, 1–36. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-30648-3_138-1.

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Klahr, Hubert, Thomas Pfeil y Andreas Schreiber. "Instabilities and Flow Structures in Protoplanetary Disks: Setting the Stage for Planetesimal Formation". En Handbook of Exoplanets, 2251–86. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-55333-7_138.

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Barnes, Rory. "Planetesimals". En Encyclopedia of Astrobiology, 1285. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_1230.

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Barnes, Rory. "Planetesimals". En Encyclopedia of Astrobiology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-27833-4_1230-6.

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Barnes, Rory. "Planetesimals". En Encyclopedia of Astrobiology, 1942. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_1230.

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Actas de conferencias sobre el tema "Planetesimal"

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Sirono, S., T. Sugino, Tomonori Usuda, Motohide Tamura y Miki Ishii. "Planetesimal Formation Induced by Sintering". En EXOPLANETS AND DISKS: THEIR FORMATION AND DIVERSITY: Proceedings of the International Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3215916.

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Young, Edward y Michelle Jordan. "IRON ISOTOPE CONSTRAINTS ON PLANETESIMAL CORE FORMATION IN THE EARLY SOLAR SYSTEM". En GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-284424.

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Saito, Etsuko, Sin-iti Sirono, Tomonori Usuda, Motohide Tamura y Miki Ishii. "Planetesimal Formation by Sublimation of Icy Dust Aggregates: effect of H[sub 2]O vapor pressure". En EXOPLANETS AND DISKS: THEIR FORMATION AND DIVERSITY: Proceedings of the International Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3215862.

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Telus, Myriam, Maggie A. Thompson y Johanna Teske. "PLANETESIMALS HERE. PLANETESIMALS THERE. PLANETESIMALS EVERYWHERE". En GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-357043.

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Carter, Philip y Sarah Stewart. "The Composition of Late-Accreted Planetesimals". En Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.330.

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Lodato, Giuseppe, Peter Cossins, Cathie Clarke, Leonardo Testi, Giuseppe Bertin, Franca De Luca, Giuseppe Lodato, Roberto Pozzoli y Massimiliano Romé. "Gravitational instabilities in protostellar discs and the formation of planetesimals". En PLASMAS IN THE LABORATORY AND THE UNIVERSE: Interactions, Patterns, and Turbulence. AIP, 2010. http://dx.doi.org/10.1063/1.3460131.

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Makino, J., E. Kokubo, T. Fukushige y H. Daisaka. "A 29.5 Tflops Simulation of Planetesimals in Uranus-Neptune Region on GRAPE-6". En ACM/IEEE SC 2002 Conference. IEEE, 2002. http://dx.doi.org/10.1109/sc.2002.10022.

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