相关论文: Compound Chondrules fused Cold
In laboratory experiments, spherical 1 mm-wide glass and basalt particles are heated, and the hot particles collide at about 1m/s with a flat glass target that is at room temperature. When the particles are heated below 900 K, the…
Chondrules are spherical or subspherical particles of crystallized or partially crystallized liquid silicates that constitute large-volume fractions of most chondritic meteorites. Chondrules typically range $0.1-2\,$mm in size and…
Shock-wave heating within the solar nebula is one of the leading candidates for the source of chondrule-forming events. Here, we examine the possibility of compound chondrule formation via optically thin shock waves. Several features of…
A leading candidate for the heating source of chondrules and igneous rims is shock waves. This mechanism generates high relative velocities between chondrules and dust particles. We have investigated the possibility of the chondrule…
We present a novel model showing that compound chondrules are formed by collisions of supercooled droplets. This model reproduces two prominent observed features of compound chondrules: the nonporphyritic texture and the size ratio between…
Chondrules are crystallised droplets of silicates formed by rapid heating to high temperatures (> 1800 K) of solid precursors followed by hours or days of cooling. Dating of chondrules is consistent with the formation timescale of Jupiter…
Compound chondrules, i.e. chondrules fused together, make a powerful probe of the density and compositional diversity in chondrule-forming environments, but their abundance among the dominating porphyritic textures may have been drastically…
Chondrules probably formed during a small window of time $\sim$1-4 Ma after CAIs, when most solid matter in the asteroid belt was already in the form of km-sized planetesimals. They are unlikely, therefore, to be ``building blocks" of…
The formation of chondrules is one of the oldest unsolved mysteries in meteoritics and planet formation. Recently an old idea has been revived: the idea that chondrules form as a result of collisions between planetesimals in which the…
We propose a new scenario for compound chondrule formation named as "fragment-collision model," in the framework of the shock-wave heating model. A molten cm-sized dust particle (parent) is disrupted in the high-velocity gas flow. The…
While sub-mm melt droplets should rapidly lose alkali elements in a vacuum at liquidus temperatures, chondrules are only modestly depleted in them (by less than one order of magnitude). The detection of sodium in olivine cores has…
As some of the most ancient materials in our Solar System, chondritic meteorites offer a valuable window into the early stages of planetary formation, particularly the accretion processes that built the most primitive asteroids. Until now,…
Shock wave heating is a leading candidate for the mechanisms of chondrule formation. This mechanism forms chondrules when the shock velocity is in a certain range. If the shock velocity is lower than this range, dust particles smaller than…
We present a mechanism for chondrules to stick together by means of compaction of a porous dust rim they sweep up as they move through the dusty nebula gas. It is shown that dust aggregates formed out of micron-sized grains stick to…
Abridged: We study the properties of clumps formed in three-dimensional weakly magnetized magneto-hydrodynamic simulations of converging flows in the thermally bistable, warm neutral medium (WNM). We find that: (1) Similarly to the…
In order to develop a complete theory of star formation, one essentially needs to know two things: what collapses, and how long it takes. This is the second paper in a series, where we query how long a parcel of gas takes to collapse and…
The formation of planetesimals in the early Solar System is hardly understood, and in particular the growth of dust aggregates above millimeter sizes has recently turned out to be a difficult task in our understanding [Zsom et al. 2010,…
It has been proposed that some meteorites, CB and CH chondrites, contain material formed as a result of a protoplanetary collision during accretion. Their melt droplets (chondrules) and FeNi metal are proposed to have formed by evaporation…
We study the coalescence of nanoscale metal clusters in an inert-gas atmosphere using constant-energy molecular dynamics. The coalescence proceeds via atomic diffusion with the release of surface energy raising the temperature. If the…
Coalescence may not occur immediately when droplets impact a liquid film. Despite the prevalence of the high-temperature condition during the impact process in many applications, the effect of droplet temperature on droplet coalescence is…