ﻻ يوجد ملخص باللغة العربية
We investigate the distribution of encounter velocities and impact angles describing collisions in the habitable zone of the early planetary system. Here we present a catalogue of collision characteristics for a particular mass ratio of the colliding bodies and seven different planetesimal masses ranging from a tenth of Ceres mass to 10 times the mass of the Moon. We show that there are virtually no collisions with impact speeds lower than the surface escape velocity and a similar velocity-impact angle distribution for different planetesimal masses if velocities are normalized using the escape velocity. An additional perturbing Jupiter-like object distorts the collision velocity and impact picture in the sense that grazing impacts at higher velocities are promoted if the perturbers orbit is close to the habitable zone whereas a more distant perturber has more the effect of a mere widening of the velocity dispersion.
Protoplanetary disks are dust-rich structures around young stars. The crystalline and amorphous materials contained within these disks are variably thermally processed and accreted to make bodies of a wide range of sizes and compositions, depending o
Collisions between large, similar-sized bodies are believed to shape the final characteristics and composition of terrestrial planets. Their inventories of volatiles such as water, are either delivered or at least significantly modified by such event
The planetary building blocks that formed in the terrestrial planet region were likely very dry, yet water is comparatively abundant on Earth. We review the various mechanisms proposed for the origin of water on the terrestrial planets. Various in-si
From modeling the evolution of disks of planetesimals under the influence of planets, it has been shown that the mass of water delivered to the Earth from beyond Jupiters orbit could be comparable to the mass of terrestrial oceans. A considerable por
The water content of magma oceans is widely accepted as a key factor that determines whether a terrestrial planet is habitable. Water ocean mass is determined as a result not only of water delivery and loss, but also of water partitioning among sever