Results 41 to 50 of about 2,944 (214)
The missing large impact craters on Ceres
Studying craters on atmosphere-less bodies can unlock information about planetesimal histories. Here, Marchi et al. present results from the NASA Dawn mission to Ceres showing that craters >100–150 km in size are largely absent, and find that Ceres ...
S. Marchi+14 more
doaj +1 more source
Silicate–sulfide interaction within quenched melts of space weathered Ryugu grains
Abstract The first few microns of the surface of airless bodies are subject to severe changes due to the harsh environment of space, known as space weathering. The Hayabusa2 sample return mission from the asteroid Ryugu provides the first opportunity to study these effects on a carbonaceous and hydrated body.
Sylvain Laforet+9 more
wiley +1 more source
Dust Evolution and the Formation of Planetesimals [PDF]
The solid content of circumstellar disks is inherited from the interstellar medium: dust particles of at most a micrometer in size. Protoplanetary disks are the environment where these dust grains need to grow at least 13 orders of magnitude in size. Our understanding of this growth process is far from complete, with different physics seemingly posing ...
Anders Johansen+3 more
openaire +4 more sources
Abstract Meteorite collection inventories show that many related meteorite groups have very different numerical abundances (e.g., lunar versus Martian meteorites; Eagle Station pallasites versus main‐group pallasites; eucrites versus diogenites; ungrouped Antarctic irons versus ungrouped non‐Antarctic irons; carbonaceous chondrite‐related (CC) iron ...
Alan E. Rubin
wiley +1 more source
Formation of pebble-pile planetesimals [PDF]
The first stage of planet formation is the accumulation of dust and ice grains into mm-cm-sized pebbles. These pebbles can clump together through the streaming instability and form gravitationally bound pebble 'clouds'. Pebbles inside such a cloud will undergo mutual collisions, dissipating energy into heat.
Karl Wahlberg Jansson, Anders Johansen
openaire +3 more sources
Magnesium phosphate in the Cold Bokkeveld (CM2) carbonaceous chondrite
Abstract Hydrous Mg‐phosphate was first described from astromaterials in particles returned from the C‐type asteroid Ryugu, and has subsequently been found in samples of the B‐type asteroid Bennu and CI1 carbonaceous chondrites. This phase may have been highly significant as a source of bioessential compounds for early Earth.
Martin R. Lee+2 more
wiley +1 more source
Abstract We investigate the melt production of planetary impacts as a function of planet size (R/REarth $R/{R}_{\text{Earth}}$ = 0.1–1.5), impactor size (L $L$ = 1–1,000 km), and core size ratio (Rcore/R ${R}_{\text{core}}/R$ = 0.2–0.8) using a combination of parameterized convection models and fully dynamical 2D impact simulations.
Lukas Manske+6 more
wiley +1 more source
Streaming Instability and Turbulence: Conditions for Planetesimal Formation
The streaming instability (SI) is a leading candidate for planetesimal formation, which can concentrate solids through two-way aerodynamic interactions with the gas.
Jeonghoon Lim+8 more
doaj +1 more source
Evidence for phosphate metasomatism in an olivine‐rich achondrites
Abstract Brachinites, brachinite‐like achondrites (BLA), and other similar primitive achondrites offer important constraints on differentiation processes of the earliest formed planetesimals, as they quenched amidst early differentiation processes on their parent body. Geochemical data for all major mineral phases in two previously poorly characterized
Robert W. Nicklas+5 more
wiley +1 more source
Planetesimal Growth in Evolving Protoplanetary Disks: Constraints from the Pebble Supply
In the core accretion model, planetesimals grow by mutual collisions and engulfing millimeter-to-centimeter particles, i.e., pebbles. Pebble accretion can significantly increase the accretion efficiency and help explain the presence of planets on wide ...
Tong Fang+4 more
doaj +1 more source