scholarly journals Migration of comets to the terrestrial planets

2006 ◽  
Vol 2 (S236) ◽  
pp. 55-64
Author(s):  
Sergei I. Ipatov ◽  
John C. Mather
Keyword(s):  
Orbital Evolution ◽  
Point Of View ◽  
Giant Planets ◽  
Terrestrial Planets ◽  
Long Period ◽  
The Earth ◽  
Near Earth Objects

AbstractWe studied the orbital evolution of objects with initial orbits close to those of Jupiter-family comets (JFCs), Halley-type comets (HTCs), and long-period comets, and the probabilities of their collisions with the 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 the contribution of such a few objects, the probability of a collision of a former JFC with the Earth during the dynamical lifetime of the comet was greater than 4×10−6. This probability is enough for delivery of all the water to Earth's oceans during the formation of the giant planets. The ratios of probabilities of collisions of JFCs and HTCs with Venus and Mars to the mass of the planet usually were not smaller than that with Earth. Among 30,000 considered objects with initial orbits close to those of JFCs, a few objects got Earth-crossing orbits with semimajor axesa<2 AU and aphelion distancesQ<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 Myr). 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.

scholarly journals Forming terrestrial planets and delivering water

2015 ◽  
Vol 11 (A29B) ◽  
pp. 427-430
Author(s):  
Kevin J. Walsh
Keyword(s):  
Planet Formation ◽  
Semimajor Axis ◽  
Giant Planet ◽  
Terrestrial Planet ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Terrestrial Planets ◽  
The Earth ◽  
Building Models ◽  
Rich Material

AbstractBuilding models capable of successfully matching the Terrestrial Planet's basic orbital and physical properties has proven difficult. Meanwhile, improved estimates of the nature of water-rich material accreted by the Earth, along with the timing of its delivery, have added even more constraints for models to match. While the outer Asteroid Belt seemingly provides a source for water-rich planetesimals, models that delivered enough of them to the still-forming Terrestrial Planets typically failed on other basic constraints - such as the mass of Mars.Recent models of Terrestrial Planet Formation have explored how the gas-driven migration of the Giant Planets can solve long-standing issues with the Earth/Mars size ratio. This model is forced to reproduce the orbital and taxonomic distribution of bodies in the Asteroid Belt from a much wider range of semimajor axis than previously considered. In doing so, it also provides a mechanism to feed planetesimals from between and beyond the Giant Planet formation region to the still-forming Terrestrial Planets.

On the ejection of Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015

2010 ◽  
Vol 10 (1) ◽  
pp. 1-13 ◽  
Author(s):  
K.E. Yeager ◽  
J. Eberle ◽  
M. Cuntz
Keyword(s):  
Statistical Study ◽  
Large Range ◽  
Giant Planet ◽  
Giant Planets ◽  
Terrestrial Planets ◽  
Survival Times ◽  
Ejection Time ◽  
The Earth ◽  
Habitable Zones ◽  
The Masses

AbstractWe provide a detailed statistical study of the ejection of fictitious Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015. These systems possess a giant planet that crosses into the stellar habitable zone, thus effectively thwarting the possibility of habitable terrestrial planets. In the case of HD 188015, the orbit of the giant planet is essentially circular, whereas in the case of HD 20782, it is extremely elliptical. As starting positions for the giant planets, we consider both the apogee and perigee positions, whereas the starting positions of the Earth-mass planets are widely varied. For the giant planets, we consider models based on their minimum masses as well as models where the masses are increased by 30%. Our simulations indicate a large range of statistical properties concerning the ejection of the Earth-mass planets from the stellar habitable zones. For example, it is found that the ejection times for the Earth-mass planets from the habitable zones of HD 20782 and HD 188015, originally placed at the centre of the habitable zones, vary by a factor of ~200 and ~1500, respectively, depending on the starting positions of the giant and terrestrial planets. If the mass of the giant planet is increased by 30%, the variation in ejection time for HD 188015 increases to a factor of ~6000. However, the short survival times of any Earth-mass planets in these systems are of no surprise. It is noteworthy, however, that considerable differences in the survival times of the Earth-mass planets are found, which may be relevant for establishing guidelines of stability for systems with less intrusive giant planets.

scholarly journals Collision probabilities of migrating small bodies and dust particles with planets

2009 ◽  
Vol 5 (S263) ◽  
pp. 41-44 ◽  
Author(s):  
Sergei I. Ipatov
Keyword(s):  
Giant Planets ◽  
Dust Particles ◽  
Total Probability ◽  
Small Bodies ◽  
Long Period ◽  
The Earth

AbstractProbabilities 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.

scholarly journals On the orbital evolution of 2020 AV2, the first asteroid ever observed to go around the Sun inside the orbit of Venus

2020 ◽  
Vol 494 (1) ◽  
pp. L6-L10 ◽  
Author(s):  
C de la Fuente Marcos ◽  
R de la Fuente Marcos
Keyword(s):  
Orbital Evolution ◽  
Gravitational Perturbation ◽  
The Sun ◽  
Moon System ◽  
Resonant Orbit ◽  
The Earth ◽  
Short Period ◽  
Orbital Periods ◽  
Near Earth Objects

ABSTRACT The innermost section of the Solar system has not been extensively studied because minor bodies moving inside Earth’s orbit tend to spend most of their sidereal orbital periods at very low solar elongation, well away from the areas more frequently observed by programs searching for near-Earth objects. The survey carried out from the Zwicky Transient Facility (ZTF) is the first one that has been able to detect multiple asteroids well detached from the direct gravitational perturbation of the Earth–Moon system. ZTF discoveries include 2019 AQ3 and 2019 LF6, two Atiras with the shortest periods among known asteroids. Here, we perform an assessment of the orbital evolution of 2020 AV2, an Atira found by ZTF with a similarly short period but following a path contained entirely within the orbit of Venus. This property makes it the first known member of the elusive Vatira population. Genuine Vatiras, those long-term dynamically stable, are thought to be subjected to the so-called von Zeipel–Lidov–Kozai oscillation that protects them against close encounters with both Mercury and Venus. However, 2020 AV2 appears to be a former Atira that entered the Vatira orbital domain relatively recently. It displays an anticoupled oscillation of the values of eccentricity and inclination, but the value of the argument of perihelion may circulate. Simulations show that 2020 AV2 might reach a 3:2 resonant orbit with Venus in the future, activating the von Zeipel–Lidov–Kozai mechanism, which in turn opens the possibility to the existence of a long-term stable population of Vatiras trapped in this configuration.

scholarly journals Comparative planetology in IPE RAS

2019 ◽  
pp. 61-77
Author(s):  
V. N. Zharkov ◽  
T. V. Gudkova
Keyword(s):  
Giant Planets ◽  
Terrestrial Planets ◽  
The Moon ◽  
Russian Academy Of Sciences ◽  
The Earth ◽  
Comparative Planetology ◽  
Academy Of Sciences ◽  
Schmidt Institute

The review of the studies on comparative planetology carried out in the Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences is presented. The obtained results are described in accordance with the study objects: the Moon, terrestrial planets, Venus and Mars, Phobos and Deimos-moons of Mars, giant planets and their moons.

scholarly journals Migration of Trans-Neptunian Objects to The Earth

1999 ◽  
Vol 172 ◽  
pp. 107-116
Author(s):  
Sergei I. Ipatov
Keyword(s):  
Computer Simulation ◽  
Kuiper Belt ◽  
Giant Planets ◽  
The Earth ◽  
Simulation Results ◽  
Near Earth Objects

AbstractMigration of trans–Neptunian objects under their mutual gravitation influence and the influence of the giant planets is investigated. These investigations are based on computer simulation results and on some formulas. We estimated that about 20 % of near–Earth objects with diameter d ≥ 1 km may have come from the Edgeworth–Kuiper belt.

scholarly journals Observational data and orbits of the asteroids discovered at the Molėtai Observatory in 2010–2012

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Ireneusz Włodarczyk ◽  
Kazimieras Černis ◽  
Justas Zdanavičius
Keyword(s):  
Observational Data ◽  
Orbital Evolution ◽  
Astronomical Observatory ◽  
The Earth ◽  
Lyapunov Time ◽  
Near Earth Objects ◽  
Orbital Analysis

AbstractThis paper is devoted to the discovery of asteroids at the Molėtai Astronomical Observatory (MAO) in 2010- 2012 together with the orbital analysis of two dynamically interesting Near Earth Objects (NEOs) discovered at the MAO, namely 2006 SF77 and 2010 BT3. We used the OrbFit software v.5.0 to compute orbits and to analyze orbital evolution of 2006 SF77 and 2010 BT3. We computed value of the Lyapunov time: 830 years for 2006 SF77 and 1650 year for 2010 BT3.We also searched for possible impacts of 2006 SF77 and 2010 BT3 with the Earth, Venus and Mars in the next 15000 years.

scholarly journals New insight into the composition and the structure of the terrestrial planet’s deep seated zones

2016 ◽  
pp. 3-9
Author(s):  
D. Yu. Pushcharovsky ◽  
Yu. M. Pushcharovsky
Keyword(s):  
Giant Planets ◽  
Terrestrial Planets ◽  
Structure And Property ◽  
Earth’S Mantle ◽  
The Earth ◽  
Property Changes ◽  
Insight Into

The structure and composition of the Earth’s mantle and of the terrestrial planets are considered in the light of the new scientific approaches. These data indicate on the further structural subdivision of the Earth’s inner geospheres and of the Moon’s deep seated zones. The results of HP- and HT-experiments related with the transformation of the main mantle’s and core’s components of the Earth, Moon, gaseus giants (Jupiter and Saturn) and ice giant planets (Uranus and Neptune) reveal the new structure and property changes.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Topographic surfaces and gravitational fields of the Earth, Moon and terrestrial planets

2000 ◽  
Vol 6 (1) ◽  
pp. 56-63
Author(s):  
K.K. Kamensky ◽  
V.S. Kislyuk ◽  
Ya.S. Yatskiv ◽  
◽  
Keyword(s):  
Terrestrial Planets ◽  
Gravitational Fields ◽  
The Earth
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