All articles tagged with #planetesimals
A new study in Nature Astronomy reveals that Earth and Mars, despite forming side-by-side in the same solar system, developed through fundamentally different processes. Earth’s mass is primarily derived from pebble accretion, while Mars’s is dominated by planetesimal collisions. Researchers analyzed volatile elements in planetary mantles to determine these distinct formation histories.
New analysis of carbonaceous iron meteorites shows the first outer-Solar-System planetesimals contained just 8–17% fine, volatile-rich matrix and 83–92% chondrules—heated rock beads formed when aluminium-26 decayed, melted interiors, and drove core formation. Aerodynamic gas drag in the protoplanetary disk caused larger chondrules to drift and concentrate while fine dust stayed with the gas, effectively filtering out much ice-rich material from the earliest bodies. This early selective construction extends a pattern seen in younger meteorites and implies the outer disk’s composition was shaped from the start by particle size and gas dynamics, not by temperature alone.
The JWST and Hubble teamed up to identify 27 newly discovered Trans-Neptunian Objects beyond Neptune, each under about 40 km across. Using infrared measurements to determine sizes and analyzing color/composition, the researchers found that the smallest TNOs retain pristine surfaces, challenging expectations that collisions would heavily alter them. The deep survey—described in two papers in The Astronomical Journal—reveals similar size distributions for both the cold Kuiper Belt and the hot scattered-disk populations, implying planetesimal formation produced comparable sizes regardless of the disk’s conditions and raising questions about the rate or effects of distant impacts.
A NASA-backed study argues Earth acquired its life-essential phosphorus and nitrogen primarily from inner Solar System planetesimals, with Jupiter's gravity redistributing materials and limiting outer Solar System contributions, challenging the idea that comets and asteroids from farther out delivered these ingredients.
Simulations suggest a dust-trap region just outside Jupiter served as a long-running nursery for planetesimals, creating two distinct populations of rocky building blocks and likely acting as a major birthplace for the solar system’s planets.
Astronomers used computer simulations to show a dust-trap ring just outside Jupiter’s orbit that concentrates material into two generations of planetesimals, potentially explaining carbonaceous chondrite meteorites found on Earth and highlighting the ring as a key birthplace for early planets in our solar system.
Simulations show a dust-loaded ring just outside Jupiter acted as a long-lasting dust trap, producing multiple generations of planetesimals with varied compositions over millions of years and linking to meteorite types like carbonaceous chondrites, offering insight into the Solar System’s early planet-building history.
New simulations show that spinning clouds of pebble-sized particles can form contact binaries—two linked bodies—and even triple planetesimals, offering a simple explanation for space snowmen in the Kuiper Belt; the study finds about 4% of simulated planetesimals become contact binaries, a share below the previously thought 10–25%, and notes that more detailed particle modeling could raise that fraction.
A new study using 54 simulations of pebble clouds (each with 100,000 particles) shows that peanut-shaped Kuiper Belt objects like Arrokoth can form through gentle gravitational collapse rather than violent impacts. About 29 of the simulations produced Arrokoth-like contact binaries, supporting the idea that such objects arise from mild formation processes, though only about 3% of the planetesimals formed a contact binary in the model, indicating more work is needed.
New computer simulations show that gentle gravitational collapse of pebble clouds in the early solar system can produce double-lobed, snowman‑like bodies such as Arrokoth, via two small planetesimals merging at about 5 meters per second to form a contact binary. The results support a gentle formation path for Kuiper belt objects, though the model predicts about 4% of objects form this way, while telescopic surveys suggest higher fractions, implying other formation routes may also contribute.
A new study on the trans-Neptunian object Arrokoth has revealed that its lobes are dotted with mounds, suggesting a common origin and shedding light on the formation of planetesimals in our solar system. The mounds share similar shape, size, color, and albedo, indicating that they clumped together to form the lobes. This discovery supports the streaming instability model of formation, where gentle collisions allow smaller objects to accumulate into larger ones. The findings may require a reevaluation of theories about planetesimal formation and could have implications for future missions targeting similar objects.
The James Webb Space Telescope has observed three concentric dusty rings of debris orbiting Fomalhaut, one of the brightest stars in our night sky located 25 light years from Earth. These three belts appear to be populated by objects called planetesimals, some of which are thought to join together early in a star system's history to form planets while others remain as debris like asteroids and comets. The observations offer insight into planetary beginnings and provide the fullest view to date of such structures outside our solar system.
A new study suggests that the degassing of early-formed planetesimals restricted the delivery of water to Earth during its formation. The research proposes that the water content of the inner solar system was initially higher than previously thought, but the process of degassing removed much of the water from the planetesimals before they could merge to form Earth. This finding sheds light on the origin of Earth's water and the volatile content of the inner solar system.