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S. I. Ipatov

Publications and source records attributed to S. I. Ipatov.

49 records · Page 3Linked to original sources
arXiv2004

Formation and Migration of Trans-Neptunian Objects

Trans-Neptunian objects (TNOs) with diameter d>100 km moving now in not very eccentric orbits could be formed directly by the compression of large rarefied dust condensations (with semi-major axes a>30 AU), but not by the accretion of smaller solid planetesimals. A considerable portion of TNO binaries could be formed at the stage of compression of condensations. Five years before the first TNO was observed, we supposed that, besides TNOs formed beyond 30 AU and moving in low eccentric orbits, there were former planetesimals from the zone of the giant planets in highly eccentric orbits beyond Neptune. For the present mass of the trans-Neptunian belt, the collisional lifetime of 1-km TNO is about the age of the solar system. At the present time TNOs can supply a large amount of matter to the near-Earth space.

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arXiv2003

Migration of Trans-Neptunian Objects to the Terrestrial Planets

The orbital evolution of more than 22000 Jupiter-crossing objects under the gravitational influence of planets was investigated. We found that the mean collision probabilities of Jupiter-crossing objects (from initial orbits close to the orbit of a comet) with the terrestrial planets can differ by more than two orders of magnitude for different comets. For initial orbital elements close to those of some comets (e.g. 2P and 10P), about 0.1% of objects got Earth-crossing orbits with semi-major axes a<2 AU and moved in such orbits for more than a Myr (up to tens or even hundreds of Myrs). Results of our runs testify in favor of at least one of these conclusions: 1) the portion of 1-km former trans-Neptunian objects (TNOs) among near-Earth objects (NEOs) can exceed several tens of percents, 2) the number of TNOs migrating inside solar system could be smaller by a factor of several than it was earlier considered, 3) most of 1-km former TNOs that had got NEO orbits disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes are not small.

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arXiv2003

Migration of Jupiter-Family Comets and Resonant Asteroids to Near-Earth Space

The orbital evolution of about 20000 Jupiter-crossing objects and 1500 resonant asteroids under the gravitational influence of planets was investigated. The rate of their collisions with the terrestrial planets was estimated by computing the probabilities of collisions based on random-phase approximations and the orbital elements sampled with a 500 yr step. The Bulirsh-Stoer and a symplectic orbit integrators gave similar results for orbital evolution, but sometimes gave different collision probabilities with the Sun. For orbits close to that of Comet 2P, the mean collision probabilities of Jupiter-crossing objects with the terrestrial planets were greater by two orders of magnitude than for some other comets. For initial orbital elements close to those of Comets 2P, 10P, 44P and 113P, a few objects (~0.1%) got Earth-crossing orbits with semi-major axes a<2 AU and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Some of them even got inner-Earth orbits (i.e., with aphelion distance Q<0.983 AU) and Aten orbits. Most former trans-Neptunian objects that have typical near-Earth object orbits moved in such orbits for millions of years (if they did not disintegrate into mini-comets), so during most of this time they were extinct comets.

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arXiv2003

Migration of Interplanetary Dust

We numerically investigate the migration of dust particles with initial orbits close to those of the numbered asteroids, observed trans-Neptunian objects, and Comet Encke. The fraction of silicate asteroidal particles that collided with the Earth during their lifetime varied from 1.1% for 100 micron particles to 0.008% for 1 micron particles. Almost all asteroidal particles with diameter d>4 microns collided with the Sun. The peaks in the migrating asteroidal dust particles' semi-major axis distribution at the n:(n+1) resonances with Earth and Venus and the gaps associated with the 1:1 resonances with these planets are more pronounced for larger particles. The probability of collisions of cometary particles with the Earth is smaller than for asteroidal particles, and this difference is greater for larger particles.

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arXiv2003

Comet and Asteroid Hazard to the Terrestrial Planets

We estimated the rate of comet and asteroid collisions with the terrestrial planets by calculating the orbits of 13000 Jupiter-crossing objects (JCOs) and 1300 resonant asteroids and computing the probabilities of collisions based on random-phase approximations and the orbital elements sampled with a 500 yr step. The Bulirsh-Stoer and a symplectic orbit integrator gave similar results for orbital evolution, but may give different collision probabilities with the Sun. A small fraction of former JCOs reached orbits with aphelia inside Jupiter's orbit, and some reached Apollo orbits with semi-major axes less than 2 AU, Aten orbits, and inner-Earth orbits (with aphelia less than 0.983 AU) and remained there for millions of years. Though less than 0.1% of the total, these objects were responsible for most of the collision probability of former JCOs with Earth and Venus. We conclude that a significant fraction of near-Earth objects could be extinct comets that came from the trans-Neptunian region.

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arXiv2003

Migration of Asteroidal Dust

We numerically investigate the migration of dust particles with initial orbits close to those of the numbered asteroids. The fraction of silicate particles that collided with the Earth during their lifetimes varied from 0.2% for 40 micron particles to 0.008% for 1 micron particles. Almost all particles with diameter d>4 microns collided with the Sun. The peaks in the migrating asteroidal dust particles' semi-major axis distribution at the n/(n+1) resonances with Earth and Venus and the gaps associated with the 1:1 resonances with these planets are more pronounced for larger particles.

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arXiv2003

Migration of Jupiter-family comets and resonant asteroids to near-Earth space

We estimated the rate of comet and asteroid collisions with the terrestrial planets by calculating the orbits of 13000 Jupiter-crossing objects (JCOs) and 1300 resonant asteroids and computing the probabilities of collisions based on random-phase approximations and the orbital elements sampled with a 500 yr step. The Bulirsh-Stoer and a symplectic orbit integrator gave similar results for orbital evolution, but sometimes give different collision probabilities with the Sun. A small fraction of former JCOs reached orbits with aphelia inside Jupiter's orbit, and some reached Apollo orbits with semi-major axes less than 2 AU, Aten orbits, and inner-Earth orbits (with aphelia less than 0.983 AU) and remained there for millions of years. Though less than 0.1% of the total, these objects were responsible for most of the collision probability of former JCOs with Earth and Venus. Some Jupiter-family comets can reach inclinations i>90 deg. We conclude that a significant fraction of near-Earth objects could be extinct comets that came from the trans-Neptunian region.

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arXiv2002

Formation and migration of trans-Neptunian objects and asteroids

The evolution of thousands of orbits of Jupiter-family comets and asteroids under the gravitational influence of planets was calculated. Comparison of the results obtained by a symplectic method with those obtained by direct integration showed that a symplectic method is not always good for investigations of the orbital evolution of such bodies. Basing on the results of orbital evolution of bodies, we concluded that a considerable portion of near-Earth objects could have come from the trans-Neptunian region. Some large trans-Neptunian objects could be formed by the compression of rarefied dust condensations, but not by the accumulation of smaller planetesimals.

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arXiv2002

Formation and Migration of Trans-Neptunian Objects - Proceedings of the conference "Scientific Frontiers in Research of Extrasolar Planets"

Some large trans-Neptunian objects could be formed by the compression of rarefied dust condensations, but not by the accumulation of smaller planetesimals. A considerable portion of near-Earth objects could have come from the trans-Neptunian region. Our runs of the evolution of thousands orbits of Jupiter-family comets under the gravitational influence of planets showed that former Jupiter-family comets collide with the terrestrial planets mostly from orbits with aphelia located deep inside Jupiter's orbit.

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arXiv2002

Formation and Migration of Trans-Neptunian Objects

We suppose that some large trans-Neptunian objects could be formed directly by the compression of rarefied dust condensations of the protoplanetary disk, but not by the accretion of smaller planetesimals. About 0.0015 of former Jupiter-crossing objects can get orbits with aphelia inside Jupiter's orbit (mainly less than 4.7 AU) during more than 1 Myr. A considerable portion of near-Earth objects could have come from the trans-Neptunian belt.

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arXiv2002

Migration of asteroids from the 3/1 and 5/2 resonances with Jupiter to the Earth

The orbital evolution of asteroids from the 3:1 and 5:2 resonances with Jupiter under the gravitational influence of planets was investigated both by the Bulirsh-Stoer method and by a symplectic method. The probabilities of collisions of asteroids with the terrestrial planets were calculated for orbital elements obtained with a step of 500 yr. The ratio of asteroids from the 3:1 resonance that were ejected into hyperbolic orbits to those collided the Sun was by an order of magnitude larger for direct integrations than for a symplectic method. The probability of a collision of an asteroid with the Earth for the 3:1 resonance was by a factor of 4 larger than that for the 5:2 resonance. The ratio of the probability of a collision of a body with a planet to the mass of the planet for Mars was by a factor of 2 larger than that for Earth and Venus.

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arXiv2001

Comet Hazard to the Earth

Migration of trans-Neptunian objects to the Earth is considered. Due to the gravitational influence of large trans-Neptunian objects and mutual collisions, some objects can get such orbits, from which they can be moved inside the Solar System under the gravitational influence of planets. About 10-20% or even more 1-km Earth-crossers could have come from the Edgeworth-Kuiper belt and can move in Jupiter-crossing orbits. The number of former trans-Neptunian objects that cross the Earth's orbit moving in orbits with aphelia inside Jupiter's orbit can be of the same order of magnitude. A total mass of icy planetesimals delivered to the Earth during formation of the giant planets can be about the mass of the Earth's oceans.

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