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The Rosetta mission and its exquisite measurements have revived the debate on whether comets are pristine planetesimals or collisionally evolved objects. We investigate the collisional evolution experienced by the precursors of current comet nuclei during the early stages of the Solar System, in the context of the so-called Nice Model. We consider two environments for the collisional evolution: (1) the trans-planetary planetesimal disk, from the time of gas removal until the disk was dispersed by the migration of the ice giants, and (2) the dispersing disk during the time that the scattered disk was formed. Simulations have been performed, using different methods in the two cases, to find the number of destructive collisions typically experienced by a comet nucleus of 2km radius. In the widely accepted scenario, where the dispersal of the planetesimal disk occurred at the time of the Late Heavy Bombardment about 4Gy ago, comet-sized planetesimals have a very small chance to survive against destructive collisions in the disk. On the extreme assumption that the disk was dispersed directly upon gas removal, there is a chance for a significant fraction of the planetesimals to remain intact. However, these survivors would still bear the marks of many non-destructive impacts. Thus, the Nice Model of Solar System evolution predicts that typical km-sized comet nuclei are predominantly fragments resulting from collisions experienced by larger parent bodies. An important goal for further research is to investigate, whether the observed properties of comet nuclei are compatible with such a collisional origin.
This article reports quasi-continuous transiting events towards WD 1054-226 at d=36.2 pc and V=16.0 mag, based on simultaneous, high-cadence, multi-wavelength imaging photometry using ULTRACAM over 18 nights from 2019 to 2020 March. The predominant p
Recent years have seen growing interest in the streaming instability as a candidate mechanism to produce planetesimals. However, these investigations have been limited to small-scale simulations. We now present the results of a global protoplanetary
Aims. We investigate the feasibility of planetesimal growth in circumbinary protoplanetary disks around the observed systems Kepler- 16 and Kepler-34 under the gravitational influence of a precessing eccentric gas disk. Methods. We embed the results
Finding and characterizing extrasolar Earth analogs will rely on interpretation of the planetary systems environmental context. The total budget and fractionation between C-H-O species sensitively affect the climatic and geodynamic state of terrestri
Oumuamua was discovered passing through our Solar System on a hyperbolic orbit. It presents an apparent contradiction, with colors similar to those of volatile-rich Solar System bodies but with no visible outgassing or activity during its close appro