Delivery of Water and Volatiles to the Terrestrial Planets and the Moon

Marov, M. Ya.; Ипатов, С. И.

doi:10.1134/s0038094618050052

Cited by 18 publications

(12 citation statements)

References 37 publications

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“…For the bodies coming from beyond Jupiter's orbit and falling onto the Earth, the typical velocities of collisions with the Earth are somewhat larger than those for the NEOs originating in the asteroid belt. According to estimates by Marov and Ipatov (2018), the typical velocities of these bodies, which entered the Earth's activity sphere, are in a range of 21−24 km/s. Ipatov (2000) noted that, among the bodies that came from zones of the giant planets, the portion of bodies with Earth-crossing orbits is an order of magnitude higher than that of bodies with Mars-crossing orbits and their eccentricities usually exceed 0.6.…”

Section: Impactor Diameters Corresponding To Diameters Of Lunar Cratersmentioning

confidence: 99%

Number of Near-Earth Objects and Formation of Lunar Craters over the Last Billion Years

2020

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We compare the number of lunar craters larger than 15 km across and younger than 1.1 Ga to the estimates of the number of craters that could have been formed for 1.1 Ga if the number of near-Earth objects and their orbital elements during that time were close to the corresponding current values. The comparison was performed for craters over the entire lunar surface and in the region of the Oceanus Procellarum and maria on the near side of the Moon. In these estimates, we used the values of collision probabilities of near-Earth objects with the Moon and the dependences of the crater diameters on the impactor sizes. According to the estimates made by different authors, the number density of known Copernican craters with diameters D≥15 km in mare regions is at least double the corresponding number for the remaining lunar surface. Our estimates do not contradict the growth in the number of near-Earth objects after probable catastrophic fragmentations of large main-belt asteroids, which may have occurred over the recent 300 Ma; however, they do not prove this increase. Particularly, they do not conflict with the inference made by Mazrouei et al. (2019) that 290 Ma ago the frequency of collisions of near-Earth asteroids with the Moon increased by 2.6 times. The number of Copernican lunar craters with diameters not smaller than 15 km is probably higher than that reported by Mazrouei et al. (2019). For a probability of a collision of an Earth-crossing object (ECO) with the Earth in a year equaled to 10-8 , our estimates of the number of craters agree with the model, according to which the number densities of the 15-km Copernican craters for the whole lunar surface would have been the same as that for mare regions if the data by Losiak et al. (2015) for D < 30 km were as complete as those for D > 30 km. With this collision probability of ECOs with the Earth and for this model, the cratering rate may have been constant over the recent 1.1 Ga.

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Section: Impactor Diameters Corresponding To Diameters Of Lunar Cratersmentioning

confidence: 99%

Number of Near-Earth Objects and Formation of Lunar Craters over the Last Billion Years

2020

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“…In the composition of the Earth and the Moon, a portion of the material which came from beyond Jupiter's orbit is relatively small. If the probability of a collision with the Earth of a planetesimal from the feeding zone of Jupiter and Saturn did not exceed 10 −5 (Marov and Ipatov, 2018;Ipatov, 2019), the total mass of bodies which fell onto the Earth does not exceed 0.001m E if the total mass of planetesimals in this zone was 100m E . Some decrease of this estimate may be PROBABILITIES OF COLLISIONS OF PLANETESIMALS FROM DIFFERENT REGIONS 355 caused by the fact that a substantial portion of these planetesimals fell onto the embryo smaller than the Earth in mass.…”

Section: Probabilities Of Collisions Of Planetesimals With the Lunar mentioning

confidence: 99%

“…The orbital elements of migrated planetesimals were saved in the computer memory with a step of 500 yr. Based on the arrays of the orbital elements, similar to simulations by Ipatov and Mather (2003, 2004a, 2004b and Marov and Ipatov (2018), the probabilities of collisions of planetesimals with the planets, the Moon, and their embryos were calculated for time interval T. In this procedure, based on these arrays of the orbital elements of migrated planetesimals, the probabilities were calculated not only for collisions between the planetesimals and the planetary embryos and the Moon, which were considered in numerical integration of the equations of motion in the analysis of planetesimals' migration, but also for collisions between the planetesimals and the embryos of the other masses (though the embryos of the other masses were ignored in the integration). This kind of approach to the analysis of the growth of planetary embryos at the expense of planetesimals which initially were at different distances from the Sun has never been used before.…”

Section: Initial Data and Algorithms To Simulate The Migration Of Pla...mentioning

confidence: 99%

“…Our earlier studies (e.g., Ipatov and Mather, 2003, 2004a, 2004b, 2006Ipatov, 2010a) of the migration of bodies in the Solar System and the delivery of water and volatiles to the terrestrial planets were first based on our numerical simulation results for the migration of tens of thousands of small bodies and dust particles, which started from these bodies, under the gravitational inf luence of all planets for the case when the initial orbits of bodies were close to the orbits of known comets, while the masses and orbital elements of the planets were equal to their present values. Marov and Ipatov (2018) simulated the migration of planetesimals to the terrestrial planet zone from the feeding zone of Jupiter and Saturn and considered the delivery of water and volatiles to the terrestrial planets and the Moon. Below, we consider the migration of planetesimals to the same planets and the Moon from the feeding zone of the terrestrial planets.…”

Section: Ipatovmentioning

confidence: 99%

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Probabilities of Collisions of Planetesimals from Different Regions of the Feeding Zone of the Terrestrial Planets with the Forming Planets and the Moon

Ипатов¹

2019

Sol Syst Res

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Migration of planetesimals from the feeding zone of the terrestrial planets, which was divided into seven regions depending on the distance to the Sun, was simulated. The influence of gravity of all planets was taken into account. In some cases, the embryos of the terrestrial planets rather than the planets themselves were considered; their masses were assumed to be 0.1 or 0.3 of the current masses of the planets. The arrays of orbital elements of migrated planetesimals were used to calculate the probabilities of their collisions with the planets, the Moon, or their embryos. As distinct from the earlier modeling of the evolution of disks of the bodies coagulating in collisions, this approach makes it possible to calculate more accurately the probabilities of collisions of planetesimals with planetary embryos of different masses for some evolution stages. When studying the composition of planetary embryos formed from planetesimals, which initially were at different distances from the Sun, we considered the narrower zones, from which planetesimals came, as compared to those examined earlier, and analyzed the temporal changes in the composition of planetary embryos rather than only the final composition of planets. Based on our calculations, we drew conclusions on the process of accumulation of the terrestrial planets. The embryos of the terrestrial planets, the masses of which did not exceed a tenth of the current planetary masses, accumulated planetesimals mainly from the vicinity of their orbits. When planetesimals fell onto the embryos of the terrestrial planets from the feeding zone of Jupiter and Saturn, these embryos had not yet acquired the current masses of the planets, and the material of this zone (including water and volatiles) could be accumulated in the inner layers of the terrestrial planets and the Moon. For planetesimals which initially were at a distance of 0.7-0.9 AU from the Sun, the probabilities of their infall onto the embryos of the Earth and Venus, the mass of which is 0.3 of the present masses of the planets, differed less than twofold for these embryos. The total mass of planetesimals, which initially were in each part of the region between 0.7 and 1.5 AU from the Sun and collided with the almost-formed Earth and Venus, apparently differed by less than two times for these planets. The inner layers of each of the terrestrial planets were mainly formed from the material located in the vicinity of the orbit of a certain planet. The outer layers of the Earth and Venus could accumulate the same material for these two planets from different parts of the feeding zone of the terrestrial planets. The Earth and Venus could acquire more than half of their masses in 5 Myr. The material ejection that occurred in impacts of bodies with the planets, which was not taken into account in the model, may enlarge the accumulation time for the planets. A relatively rapid growth of the bulk of the Martian mass can be explained by the formation of Mars' embryo (the mass of which is several times less than that of...

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“…Based on our runs of migration of planetesimals from the feeding zone of Jupiter and Saturn (Marov & Ipatov 2018) and from different distances from the Sun (from 5 to 40 AU) (Ipatov 2018b) and of migration of Jupiter-crossing objects (Ipatov & Mather 2007), I calculated probabilities of collisions of such planetesimals and objects with the Moon. Such probabilities were typically smaller than the probabilities of collisions with the Earth by a factor of 16 or 17 for the planetesimals and many Jupiter-family comets.…”

Section: Growth Of Solid Embryos Of the Earth-moon Systemmentioning

confidence: 99%

Formation of the Earth-Moon system

Ипатов

2018

Proc. IAU

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Trans-Neptunian satellite systems and embryos of the Earth-Moon system could be formed as a result of contraction of rarefied condensations. The angular momenta of rarefied condensations needed for such formation could be acquired at collisions of condensations. The angular momentum of the present Earth-Moon system could be acquired at a collision of two rarefied condensations with a total mass not smaller than 0.1ME, where ME is the mass of the Earth. The mass of the condensation that was a parent for the embryos of the Earth and the Moon could be about 0.01ME, if we take into account the growth of the angular momentum of the embryos with growth of their masses. The Moon embryo could get by an order of magnitude more material ejected from the Earth embryo than that fell directly onto the Moon embryo.

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Delivery of Water and Volatiles to the Terrestrial Planets and the Moon

Cited by 18 publications

References 37 publications

Number of Near-Earth Objects and Formation of Lunar Craters over the Last Billion Years

Number of Near-Earth Objects and Formation of Lunar Craters over the Last Billion Years

Probabilities of Collisions of Planetesimals from Different Regions of the Feeding Zone of the Terrestrial Planets with the Forming Planets and the Moon

Formation of the Earth-Moon system

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