Migration of small bodies and dust to the terrestrial planets (original) (raw)

Migration of comets to the terrestrial planets

Proceedings of the International Astronomical Union, 2006

We studied the orbital evolution of Jupiter-family comets (JFCs), Halley-type comets (HTCs), and long-period comets, and probabilities of their collisions with planets. In our runs the probability of a collision of one object with the Earth could be greater than the sum of probabilities for thousands of other objects. Even without a contribution of such a few bodies, the probability of a collision of a former JFC with the Earth was greater than 4·10 −6 . This probability is enough for delivery of all the water to Earth's oceans during formation of the giant planets. The ratios of probabilities of collisions of JFCs and HTCs with Venus and Mars to the mass of a planet usually were not smaller than that for Earth. Among 30,000 considered objects with initial orbits close to those of JFCs, a few objects got Earth-crossing orbits with semi-major axes a<2 AU and aphelion distances Q<4.2 AU, or even got inner-Earth (Q<0.983 AU), Aten, or typical asteroidal orbits, and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). From a dynamical point of view, the fraction of extinct comets among near-Earth objects can exceed several tens of percent, but, probably, many extinct comets disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes were large.

Migration of Trans-Neptunian Objects to the Terrestrial Planets

Earth, Moon, and Planets, 2000

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.

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

Annals of the New York Academy of Sciences, 2004

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 randomphase 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.

Migration of small bodies and dust to near-Earth space

Advances in Space Research, 2006

The orbital evolution of Jupiter-family comets (JFCs) and asteroidal, trans-Neptunian, and cometary dust particles under the gravitational influence of planets was integrated. For dust particles, we also considered the Poynting-Robertson drag, radiation pressure, and solar wind drag. Results of our runs were compared with the spacecraft observations of the spatial density of dust particles and with the WHAM observations of velocities of zodiacal particles. This comparison shows that the fraction of cometary dust particles of the overall dust population inside SaturnÕs orbit is significant and can be dominant. Our studies of migration of small bodies indicate that some former JFCs could move for millions of years inside JupiterÕs orbit and so they could produce a lot of dust. The probability of a collision of an asteroidal or cometary dust particle with the Earth during its lifetime was maximum at diameter d $ 100 lm. At d < 10 lm, the probability of a collision of a trans-Neptunian particle with the Earth during a lifetime of the particle was less than that for an asteroidal particle by only a factor of several.

Collision probabilities of migrating small bodies and dust particles with planets

Proceedings of the International Astronomical Union, IAU Symposium, IAU vol. 5, Symposium S263, "Icy bodies in the Solar System" (Rio de Janeiro, Brazil, 3-7 August, 2009), ed. by J.A. Fernandez, D. Lazzaro, D. Prialnik, R. Schulz, Cambridge University Press, pp. 41-44 , 2010

Probabilities of collisions of migrating small bodies and dust particles produced by these bodies with planets were studied. Various Jupiter-family comets, Halley-type comets, long-period comets, trans-Neptunian objects, and asteroids were considered. The total probability of collisions of any considered body or particle with all planets did not exceed 0.2. The amount of water delivered from outside of Jupiter's orbit to the Earth during the formation of the giant planets could exceed the amount of water in Earth's oceans. The ratio of the mass of water delivered to a planet by Jupiter-family comets or Halley-type comets to the mass of the planet can be greater for Mars, Venus, and Mercury, than that for Earth.

Migration of Interplanetary Dust

Annals of the New York Academy of Sciences, 2004

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.

Contamination of the asteroid belt by primordial trans-Neptunian objects

Nature, 2009

The main asteroid belt, which inhabits a relatively narrow annulus 2.1-3.3 AU from the Sun, contains a surprising diversity of objects ranging from primitive ice-rock mixtures to igneous rocks. The standard model used to explain this assumes that most asteroids formed in situ from a primordial disk that experienced radical chemical changes within this zone 1 . Here we show that the violent dynamical evolution of the giant-planet orbits required by the socalled Nice model 2-4 leads to the insertion of primitive trans-Neptunian objects into the outer belt. This result implies that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk. The dark captured bodies, composed of organic-rich materials, would have been more susceptible to collisional evolution than typical main-belt asteroids. Their weak nature makes them a prodigious source of micrometeorites-sufficient to explain why most are primitive in composition and are isotopically different from most macroscopic meteorites 5,6 .

Formation and migration of trans-Neptunian objects and asteroids

arXiv: Astrophysics, 2002

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.

Migration of dust particles to the terrestrial planets

2006

The orbital evolution of asteroidal, trans-Neptunian, and cometary dust particles under the gravitational influence of planets, the Poynting-Robertson drag, radiation pressure, and solar wind drag was integrated. Results of our runs were compared with the spacecraft observations of the number density of dust particles and with the WHAM observations of velocities of zodiacal particles. This comparison shows that the fraction of cometary dust particles of the overall dust population inside Saturn's orbit is significant and can be dominant. The probability of a collision of an asteroidal or cometary dust particle with the Earth during its dynamical lifetime is maximum at diameter d~100 µm.

Migration of celestial bodies in the solar system and in some exoplanetary systems

Solar System Research, 2024

A review of the results on the migration of celestial bodies in the Solar System and in some exoplanetary systems is presented. Some problems of planet accumulation and migration of planetesimals, small bodies and dust in the forming and present Solar System are considered. It has been noted that the outer layers of the Earth and Venus could have accumulated similar planetesimals from different areas of the feeding zone of the terrestrial planets. In addition to the theory of coaccretion and the mega-impact and multi-impact models, the formation of the embryos of the Earth and the Moon from a common rarefied condensation with subsequent growth of the main mass of the embryo of the Moon near the Earth is also discussed. Along with the Nice model and the “grand tack” model, a model is considered in which the embryos of Uranus and Neptune increased the semimajor axes of their orbits from values of no more than 10 AU to present values only due to gravitational interactions with planetesimals (without the motions of Jupiter and Saturn entering into resonance). The influence of changes in the semimajor axis of Jupiter’s orbit on the formation of the asteroid belt is discussed, as well as the influence of planetesimals from the feeding zone of the giant planets on the formation of bodies beyond the orbit of Neptune. The migration of bodies to the terrestrial planets from different distances from the Sun is considered. It is noted that bodies from the feeding zone of the giant planets and from the outer asteroid belt could deliver to the Earth a quantity of water comparable to the mass of water in the Earth’s oceans. The migration of bodies ejected from the Earth is considered. It is noted that about 20% of the ejected bodies that left the Earth’s sphere of influence eventually fell back to the Earth. The probabilities of collisions of dust particles with the Earth are usually an order of magnitude greater than the probabilities of collisions of their parent bodies with the Earth. The migration of planetesimals is considered in exoplanetary systems Proxima Centauri and TRAPPIST-1. The amount of water delivered to the inner planet Proxima Centauri b, may have been more than the amount delivered to the Earth. The outer layers of neighboring planets in the TRAPPIST-1 system may contain similar material if there were many planetesimals near their orbits during the late stages of planetary accumulation.