Grand tack hypothesis

Last updated
Jupiter might have shaped the Solar System on its grand tack Jupiter and its shrunken Great Red Spot.jpg
Jupiter might have shaped the Solar System on its grand tack

In planetary astronomy, the grand tack hypothesis proposes that Jupiter formed at a distance of 3.5 AU from the Sun, then migrated inward to 1.5 AU, before reversing course due to capturing Saturn in an orbital resonance, eventually halting near its current orbit at 5.2 AU. The reversal of Jupiter's planetary migration is likened to the path of a sailboat changing directions (tacking) as it travels against the wind. [1]

Contents

The planetesimal disk is truncated at 1.0 AU by Jupiter's migration, limiting the material available to form Mars. [2] Jupiter twice crosses the asteroid belt, scattering asteroids outward then inward. The resulting asteroid belt has a small mass, a wide range of inclinations and eccentricities, and a population originating from both inside and outside Jupiter's original orbit. [3] Debris produced by collisions among planetesimals swept ahead of Jupiter may have driven an early generation of planets into the Sun. [4]

Description

In the grand tack hypothesis Jupiter underwent a two-phase migration after its formation, migrating inward to 1.5  AU before reversing course and migrating outward. Jupiter's formation took place near the ice line, at roughly 3.5 AU.

After clearing a gap in the gas disk Jupiter underwent type II migration, moving slowly toward the Sun with the gas disk. If uninterrupted, this migration would have left Jupiter in a close orbit around the Sun, similar to hot Jupiters in other planetary systems. [5] Saturn also migrated toward the Sun, but being smaller it migrated faster, undergoing either type I migration or runaway migration. [6] Saturn converged on Jupiter and was captured in a 2:3 mean-motion resonance with Jupiter during this migration. An overlapping gap in the gas disk then formed around Jupiter and Saturn, [7] altering the balance of forces on these planets which began migrating together. Saturn partially cleared its part of the gap reducing the torque exerted on Jupiter by the outer disk.

The net torque on the planets then became positive, with the torques generated by the inner Lindblad resonances exceeding those from the outer disk, and the planets began to migrate outward. [8] The outward migration was able to continue because interactions between the planets allowed gas to stream through the gap. [9] The gas exchanged angular momentum with the planets during its passage, adding to the positive balance of torques, allowing the planets to migrate outward relative to the disk; the exchange also transferred mass from the outer disk to the inner disk. [10] The transfer of gas to the inner disk also slowed the reduction of the inner disk's mass relative to the outer disk as it accreted onto the Sun, which otherwise would weaken the inner torque, ending the giant planets' outward migration. [8] [11] In the grand tack hypothesis this process is assumed to have reversed the inward migration of the planets when Jupiter was at 1.5 AU. [6] The outward migration of Jupiter and Saturn continued until they reached a zero-torque configuration within a flared disk, [12] [11] or when the gas disk dissipated. [11] The whole process is presumed to end when Jupiter reached its approximate current orbit. [6]

Scope of the grand tack hypothesis

The hypothesis can be applied to multiple phenomena in the Solar System.

Mars problem

The "Mars problem" is a conflict between some simulations of the formation of the terrestrial planets which end with a 0.5–1.0  ME planet in its region, much larger than the actual mass of Mars: 0.107  ME, when begun with planetesimals distributed throughout the inner Solar System. Jupiter's grand tack resolves the Mars problem by limiting the material available to form Mars. [13]

Jupiter's inward migration alters this distribution of material, [14] driving planetesimals inward to form a narrow dense band with a mix of materials inside 1.0  AU, [15] and leaves the Mars region largely empty. [16] Planetary embryos quickly form in the narrow band. Most of these embryos collide and merge to form the larger terrestrial planets (Venus and Earth) over a period of 60 to 130 million years. [17] Others are scattered outside the band where they are deprived of additional material, slowing their growth, and form the lower-mass terrestrial planets Mars and Mercury. [18]

Asteroid belt

Jupiter and Saturn drive most asteroids from their initial orbits during their migrations, leaving behind an excited remnant derived from both inside and outside Jupiter's original location. Before Jupiter's migrations the surrounding regions contained asteroids which varied in composition with their distance from the Sun. [19] Rocky asteroids dominated the inner region, while more primitive and icy asteroids dominated the outer region beyond the ice line. [20] As Jupiter and Saturn migrate inward, ~15% of the inner asteroids are scattered outward onto orbits beyond Saturn. [2] After reversing course, Jupiter and Saturn first encounter these objects, scattering about 0.5% of the original population back inward onto stable orbits. [6] Later, as Jupiter and Saturn migrate into the outer region, about 0.5% of the primitive asteroids are scattered onto orbits in the outer asteroid belt. [6] The encounters with Jupiter and Saturn leave many of the captured asteroids with large eccentricities and inclinations. [16] These may be reduced during the giant planet instability described in the Nice model so that the eccentricity distribution resembles that of the current asteroid belt. [21] Some of the icy asteroids are also left in orbits crossing the region where the terrestrial planets later formed, allowing water to be delivered to the accreting planets as when the icy asteroids collide with them. [22] [23]

Absent super-Earths

The absence of close orbiting super-Earths in the Solar System may also be the result of Jupiter's inward migration. [24] As Jupiter migrates inward, planetesimals are captured in its mean-motion resonances, causing their orbits to shrink and their eccentricities to grow. A collisional cascade follows as the planetesimals' relative velocities became large enough to produce catastrophic impacts. The resulting debris then spirals inward toward the Sun due to drag from the gas disk. If there were super-Earths in the early Solar System, they would have caught much of this debris in resonances and could have been driven into the Sun as the debris spiraled inward. The current terrestrial planets would then form from planetesimals left behind when Jupiter reversed course. [25] However, the migration of close orbiting super-Earths into the Sun could be avoided if the debris coalesced into larger objects, reducing gas drag; and if the protoplanetary disk had an inner cavity, their inward migration could be halted near its edge. [26] If no planets had yet formed in the inner Solar System, the destruction of the larger bodies during the collisional cascade could have left the remaining debris small enough to be pushed outward by the solar wind, which would have been much stronger during the early Solar System, leaving little to form planets inside Mercury's orbit. [27]

Later developments

Simulations of the formation of the terrestrial planets using models of the protoplanetary disk that include viscous heating and the migration of the planetary embryos indicate that Jupiter's migration may have reversed at 2.0 AU. In simulations the eccentricities of the embryos are excited by perturbations from Jupiter. As these eccentricities are damped by the denser gas disk of recent models, the semi-major axes of the embryos shrink, shifting the peak density of solids inward. For simulations with Jupiter's migration reversing at 1.5 AU, this resulted in the largest terrestrial planet forming near Venus's orbit rather than at Earth's orbit. Simulations that instead reversed Jupiter's migration at 2.0 AU yielded a closer match to the current Solar System. [9]

When the fragmentation due to hit and run collisions are included in simulations with an early instability the orbits of the terrestrial planets are better produced. The larger numbers of small bodies resulting from these collisions reduce the eccentricities and inclinations of the growing planets orbits via additional collisions and dynamical friction. This also results in a larger fraction of the terrestrial planets mass being concentrated in Venus and Earth and extends their formation times relative to that of Mars. [28]

The migration of the giant planets through the asteroid belt creates a spike in impact velocities that could result in the formation of CB chondrites. CB chondrites are metal rich carbonaceous chondrites containing iron/nickel nodules that formed from the crystallization of impact melts 4.8 ±0.3 Myrs after the first solids. The vaporization of these metals requires impacts of greater than 18 km/s, well beyond the maximum of 12.2 km/s in standard accretion models. Jupiter's migration across the asteroid belt increases the eccentricities and inclinations of the asteroids, resulting in a 0.5 Myr period of impact velocities sufficient to vaporize metals. If the formation of CB chondrites was due to Jupiter's migration it would have occurred 4.5-5 Myrs after the formation of the Solar System. [29]

The presence of a thick atmosphere around Titan and its absence around Ganymede and Callisto may be due to the timing of their formation relative to the grand tack. If Ganymede and Callisto formed before the grand tack their atmospheres would have been lost as Jupiter moved closer to the Sun. However, for Titan to avoid Type I migration into Saturn, and for Titan's atmosphere to survive, it must have formed after the grand tack. [30] [31]

Encounters with other embryos could destabilize a disk orbiting Mars reducing the mass of moons that form around Mars. After Mars is scattered from the annulus by encounters with other planets it continues to have encounters with other objects until the planets clear material from the inner Solar System. While these encounters enable the orbit of Mars to become decoupled from the other planets and remain on a stable orbit, they can also perturb the disk of material from which the moons of Mars form. These perturbations cause material to escape from the orbit of Mars or to impact on its surface reducing the mass of the disk resulting in the formation of smaller moons. [32]

Potential problems

Most of the accretion of Mars must have taken place outside the narrow annulus of material formed by the grand tack if Mars has a different composition than Earth and Venus. The planets that grow in the annulus created by the grand tack end with similar compositions. If the grand tack occurred early, while the embryo that became Mars was relatively small, a Mars with a differing composition could form if it was instead scattered outward then inward like the asteroids. The chance of this occurring is roughly 2%. [33] [34]

Later studies have shown that the convergent orbital migration of Jupiter and Saturn in the fading solar nebula is unlikely to establish a 3:2 mean-motion resonance. Instead of supporting a faster runaway migration, nebula conditions lead to a slower migration of Saturn and its capture in a 2:1 mean-motion resonance. [11] [35] [36] Capture of Jupiter and Saturn in the 2:1 mean-motion resonance does not typically reverse the direction of migration, but particular nebula configurations have been identified that may drive outward migration. [37] These configurations, however, tend to excite Jupiter's and Saturn's orbital eccentricity to values between two and three times as large as their actual values. [37] [38] Also, if the temperature and viscosity of the gas allow Saturn to produce a deeper gap, the resulting net torque can again become negative, resulting in the inward migration of the system. [11]

The grand tack scenario ignores the ongoing accretion of gas on both Jupiter and Saturn. [39] In fact, to drive outward migration and move the planets to the proximity of their current orbits, the solar nebula had to contain a sufficiently large reservoir of gas around the orbits of the two planets. However, this gas would provide a source for accretion, which would affect the growth of Jupiter and Saturn and their mass ratio. [11] The type of nebula density required for capture in the 3:2 mean-motion resonance is especially dangerous for the survival of the two planets, because it can lead to significant mass growth and ensuing planet-planet scattering. But conditions leading to 2:1 mean-motion resonant systems may also put the planets in danger. [40] Accretion of gas on both planets also tends to reduce the supply toward the inner disk, lowering the accretion rate toward the Sun. This process works to deplete somewhat the disk interior to Jupiter's orbit, weakening the torques on Jupiter arising from inner Lindblad resonances and potentially ending the planets' outward migration. [11]

Alternatives

Multiple hypotheses have been offered to explain the small mass of Mars. A small Mars may have been a low probability event as it occurs in a small, but non-zero, fraction of simulations that begin with planetesimals distributed across the entire inner Solar System. [41] [42] [43] A small Mars could be the result of its region having been largely empty due to solid material drifting farther inward before the planetesimals formed. [44] [45] Most of the mass could also have been removed from the Mars region before it formed if the giant planet instability described in the Nice model occurred early. [46] [47] If most of the growth of planetesimals and embryos into terrestrial planets was due to pebble accretion, a small Mars could be the result this process having been less efficient with increasing distances from the Sun. [48] [49] Convergent migration of planetary embryos in the gas disk toward 1 AU would result in the formation of terrestrial planets only near this distance leaving Mars as a stranded embryo. [50] Sweeping secular resonances during the clearing of the gas disk could also excite inclinations and eccentricities, increasing relative velocities so that collisions resulted in fragmentation instead of accretion. [51] A number of these hypotheses could also explain the low mass of the asteroid belt.

A number of hypotheses have also been proposed to explain the orbital eccentricities and inclinations of the asteroids and the low mass of the asteroid belt. If the region of the asteroid belt was initially empty due to few planetesimals forming there it could have been populated by icy planetesimals that were scattered inward during Jupiter's and Saturn's gas accretion, [52] and by stony asteroids that were scattered outward by the forming terrestrial planets. [53] [54] The inward scattered icy planetesimals could also deliver water to the terrestrial region. [55] An initially low-mass asteroid belt could have had its orbital eccentricities and inclinations excited by secular resonances if the resonant orbits of Jupiter and Saturn became chaotic before the instability of the Nice model. [56] [57] The eccentricities and inclinations of the asteroid could also be excited during the giant planet instability, reaching the observed levels if it lasted for a few hundred thousand years. [58] Gravitational interactions between the asteroids and embryos in an initially massive asteroid belt would enhance these effects by altering the asteroids semi-major axes, driving many asteroids into unstable orbits where they were removed due to interactions with the planets, resulting in the loss of more than 99% of its mass. [59] Secular resonance sweeping during the dissipation of the gas disk could have excited the orbits of the asteroids and removed many as they spiraled toward the Sun due to gas drag after their eccentricities were excited. [60]

Several hypotheses have also been offered for the lack of close orbiting super-Earth and the small mass of Mercury. If Jupiter's core formed close to the Sun, its outward migration across the inner Solar System could have pushed material outward in its resonances, leaving the region inside Venus's orbit depleted. [61] [26] In a protoplanetary disk that was evolving via a disk wind, planetary embryos could have migrated outward before merging to form planets, leaving the Solar System without planets inside Mercury's orbit. [62] [63] Convergent migration of planetary embryos in the gas disk toward 1 AU would also have resulted in the formation of large terrestrial planets near this distance leaving Mercury as a stranded embryo. [50] An early generation of inner planets could have been lost due to catastrophic collisions during an instability, resulting in the debris being ground small enough to be lost due to Poynting-Robertson drag. [64] [65] If planetesimal formation only occurred early, the inner edge of the planetesimal disk might have been located at the silicate condensation line at this time. [66] The formation of planetesimals closer than Mercury's orbit may have required that the magnetic field of the star be aligned with the rotation of the disk, enabling the depletion of the gas so that solid to gas ratios reached values sufficient for streaming instabilities to occur. [67] [68] The formation of super-Earths may require a higher flux of inward drifting pebbles than occurred in the early Solar System. [69] Planetesimals orbiting in a protoplanetary disk closer than 0.6 AU may have eroded away due to a headwind. [70] An early Solar System that was largely depleted of material could have resulted in the formation of small planets that were lost or destroyed in an early instability leaving only Mercury or the formation of only Mercury. [71] [72]

See also

Related Research Articles

<span class="mw-page-title-main">Kuiper belt</span> Area of the Solar System beyond the planets, comprising small bodies

The Kuiper belt is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles, such as methane, ammonia, and water. The Kuiper belt is home to most of the objects that astronomers generally accept as dwarf planets: Orcus, Pluto, Haumea, Quaoar, and Makemake. Some of the Solar System's moons, such as Neptune's Triton and Saturn's Phoebe, may have originated in the region.

<span class="mw-page-title-main">Jupiter trojan</span> Asteroid sharing the orbit of Jupiter

The Jupiter trojans, commonly called trojan asteroids or simply trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each trojan librates around one of Jupiter's stable Lagrange points: either L4, existing 60° ahead of the planet in its orbit, or L5, 60° behind. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU.

<span class="mw-page-title-main">Planetesimal</span> Solid objects in protoplanetary disks and debris disks

Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation.

<span class="mw-page-title-main">Nebular hypothesis</span> Astronomical theory about the Solar System

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System. It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heavens (1755) and then modified in 1796 by Pierre Laplace. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model. It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the original nebular theory are echoed in modern theories of planetary formation, but most elements have been superseded.

<span class="mw-page-title-main">Protoplanetary disk</span> Gas and dust surrounding a newly formed star

A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may not be considered an accretion disk, while the two are similar. While they are similar, an accretion disk is hotter, and spins much faster. It is also found on black holes, not stars. This process should not be confused with the accretion process thought to build up the planets themselves. Externally illuminated photo-evaporating protoplanetary disks are called proplyds.

<span class="mw-page-title-main">Planetary migration</span> Astronomical phenomenon

Planetary migration occurs when a planet or other body in orbit around a star interacts with a disk of gas or planetesimals, resulting in the alteration of its orbital parameters, especially its semi-major axis. Planetary migration is the most likely explanation for hot Jupiters. The generally accepted theory of planet formation from a protoplanetary disk predicts that such planets cannot form so close to their stars, as there is insufficient mass at such small radii and the temperature is too high to allow the formation of rocky or icy planetesimals.

<span class="mw-page-title-main">Accretion (astrophysics)</span> Accumulation of particles into a massive object by gravitationally attracting more matter

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.

<span class="mw-page-title-main">Ice giant</span> Giant planet primarily consisting of compounds with freezing points exceeding 100°K

An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur. There are two ice giants in the Solar System: Uranus and Neptune.

In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the minimum distance from the central protostar of a solar nebula where the temperature is low enough for volatile compounds such as water, ammonia, methane, carbon dioxide and carbon monoxide to condense into solid grains, which will allow their accretion into planetesimals. Beyond the line, otherwise gaseous compounds can be quite easily condensed to allow formation of gas and ice giants; while within it, only heavier compounds can be accreted to form the typically much smaller rocky planets.

<span class="mw-page-title-main">Formation and evolution of the Solar System</span>

There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed.

<span class="mw-page-title-main">Nice model</span> Scenario for the dynamical evolution of the Solar System

In astronomy, the Nicemodel is a scenario for the dynamical evolution of the Solar System. It is named for the location of the Côte d'Azur Observatory—where it was initially developed in 2005—in Nice, France. It proposes the migration of the giant planets from an initial compact configuration into their present positions, long after the dissipation of the initial protoplanetary disk. In this way, it differs from earlier models of the Solar System's formation. This planetary migration is used in dynamical simulations of the Solar System to explain historical events including the Late Heavy Bombardment of the inner Solar System, the formation of the Oort cloud, and the existence of populations of small Solar System bodies such as the Kuiper belt, the Neptune and Jupiter trojans, and the numerous resonant trans-Neptunian objects dominated by Neptune.

<span class="nowrap">(120216) 2004 EW<sub>95</sub></span>

(120216) 2004 EW95 (provisional designation 2004 EW95) is a resonant trans-Neptunian object in the Kuiper belt located in the outermost regions of the Solar System. It measures approximately 291 kilometers in diameter. It has more carbon than typical of KBOs, and the first to be confirmed as having this composition in this region of space. It is thought to have originated closer to the Sun, perhaps even in the main asteroid belt.

<span class="mw-page-title-main">Late Heavy Bombardment</span> Hypothesized astronomical event

The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized astronomical event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. According to the hypothesis, during this interval, a disproportionately large number of asteroids and comets collided into the terrestrial planets and their natural satellites in the inner Solar System, including Mercury, Venus, Earth and Mars. These came from both post-accretion and planetary instability-driven populations of impactors. Although it gained widespread credence, definitive evidence remains elusive.

The five-planet Nice model is a numerical model of the early Solar System that is a revised variation of the Nice model. It begins with five giant planets, the four that exist today plus an additional ice giant between Saturn and Uranus in a chain of mean-motion resonances.

<span class="mw-page-title-main">E-belt asteroids</span> Hypothetical extension of the asteroid belt

The E-belt asteroids were the population of a hypothetical extension of the primordial asteroid belt proposed as the source of most of the basin-forming lunar impacts during the Late Heavy Bombardment.

The jumping-Jupiter scenario specifies an evolution of giant-planet migration described by the Nice model, in which an ice giant is scattered inward by Saturn and outward by Jupiter, causing their semi-major axes to jump, and thereby quickly separating their orbits. The jumping-Jupiter scenario was proposed by Ramon Brasser, Alessandro Morbidelli, Rodney Gomes, Kleomenis Tsiganis, and Harold Levison after their studies revealed that the smooth divergent migration of Jupiter and Saturn resulted in an inner Solar System significantly different from the current Solar System. During this migration secular resonances swept through the inner Solar System exciting the orbits of the terrestrial planets and the asteroids, leaving the planets' orbits too eccentric, and the asteroid belt with too many high-inclination objects. The jumps in the semi-major axes of Jupiter and Saturn described in the jumping-Jupiter scenario can allow these resonances to quickly cross the inner Solar System without altering orbits excessively, although the terrestrial planets remain sensitive to its passage.

The Nice 2 model is a model of the early evolution of the Solar System. The Nice 2 model resembles the original Nice model in that a late instability of the outer Solar System results in gravitational encounters between planets, the disruption of an outer planetesimal disk, and the migrations of the outer planets to new orbits. However, the Nice 2 model differs in its initial conditions and in the mechanism for triggering the late instability. These changes reflect the analysis of the orbital evolution of the outer Solar System during the gas disk phase and the inclusion of gravitational interactions between planetesimals in the outer disk into the model.

<span class="mw-page-title-main">Satellite system (astronomy)</span> Set of gravitationally bound objects in orbit

A satellite system is a set of gravitationally bound objects in orbit around a planetary mass object or minor planet, or its barycenter. Generally speaking, it is a set of natural satellites (moons), although such systems may also consist of bodies such as circumplanetary disks, ring systems, moonlets, minor-planet moons and artificial satellites any of which may themselves have satellite systems of their own. Some bodies also possess quasi-satellites that have orbits gravitationally influenced by their primary, but are generally not considered to be part of a satellite system. Satellite systems can have complex interactions including magnetic, tidal, atmospheric and orbital interactions such as orbital resonances and libration. Individually major satellite objects are designated in Roman numerals. Satellite systems are referred to either by the possessive adjectives of their primary, or less commonly by the name of their primary. Where only one satellite is known, or it is a binary with a common centre of gravity, it may be referred to using the hyphenated names of the primary and major satellite.

<span class="mw-page-title-main">Pebble accretion</span>

Pebble accretion is the accumulation of particles, ranging from centimeters up to meters in diameter, into planetesimals in a protoplanetary disk that is enhanced by aerodynamic drag from the gas present in the disk. This drag reduces the relative velocity of pebbles as they pass by larger bodies, preventing some from escaping the body's gravity. These pebbles are then accreted by the body after spiraling or settling toward its surface. This process increases the cross section over which the large bodies can accrete material, accelerating their growth. The rapid growth of the planetesimals via pebble accretion allows for the formation of giant planet cores in the outer Solar System before the dispersal of the gas disk. A reduction in the size of pebbles as they lose water ice after crossing the ice line and a declining density of gas with distance from the sun slow the rates of pebble accretion in the inner Solar System resulting in smaller terrestrial planets, a small mass of Mars and a low mass asteroid belt.

In planetary science a streaming instability is a hypothetical mechanism for the formation of planetesimals in which the drag felt by solid particles orbiting in a gas disk leads to their spontaneous concentration into clumps which can gravitationally collapse. Small initial clumps increase the orbital velocity of the gas, slowing radial drift locally, leading to their growth as they are joined by faster drifting isolated particles. Massive filaments form that reach densities sufficient for the gravitational collapse into planetesimals the size of large asteroids, bypassing a number of barriers to the traditional formation mechanisms. The formation of streaming instabilities requires solids that are moderately coupled to the gas and a local solid to gas ratio of one or greater. The growth of solids large enough to become moderately coupled to the gas is more likely outside the ice line and in regions with limited turbulence. An initial concentration of solids with respect to the gas is necessary to suppress turbulence sufficiently to allow the solid to gas ratio to reach greater than one at the mid-plane. A wide variety of mechanisms to selectively remove gas or to concentrate solids have been proposed. In the inner Solar System the formation of streaming instabilities requires a greater initial concentration of solids or the growth of solid beyond the size of chondrules.

References

  1. ↑ Zubritsky, Elizabeth. "Jupiter's Youthful Travels Redefined Solar System". NASA. Archived from the original on 1 March 2017. Retrieved 4 November 2015.
  2. 1 2 Beatty, Kelly (16 October 2010). "Our "New, Improved" Solar System". Sky & Telescope . Retrieved 4 November 2015.
  3. ↑ Sanders, Ray (23 August 2011). "How Did Jupiter Shape Our Solar System?". Universe Today . Retrieved 4 November 2015.
  4. ↑ Choi, Charles Q. (23 March 2015). "Jupiter's 'Smashing' Migration May Explain Our Oddball Solar System". Space.com. Retrieved 4 November 2015.
  5. ↑ Fesenmaier, Kimm (23 March 2015). "New research suggests Solar system may have once harbored super-Earths". Caltech . Retrieved 5 November 2015.
  6. 1 2 3 4 5 Walsh, Kevin J.; Morbidelli, Alessandro; Raymond, Sean N.; O'Brien, David P.; Mandell, Avi M. (2011). "A low mass for Mars from Jupiter's early gas-driven migration". Nature . 475 (7355): 206–209. arXiv: 1201.5177 . Bibcode:2011Natur.475..206W. doi:10.1038/nature10201. PMID   21642961. S2CID   4431823.
  7. ↑ "New research suggests solar system may have once harbored super-Earths". Astrobiology . Retrieved 5 November 2015.
  8. 1 2 Morbidelli, Alessandro; Crida, Aurélien (2007). "The dynamics of Jupiter and Saturn in the gaseous protoplanetary disk". Icarus. 191 (1): 158–171. arXiv: 0704.1210 . Bibcode:2007Icar..191..158M. doi:10.1016/j.icarus.2007.04.001. S2CID   17672873.
  9. 1 2 Brasser, R.; Matsumura, S.; Ida, S.; Mojzsis, S.J.; Werner, S.C. (2016). "Analysis of terrestrial planet formation by the Grand Tack model: System architecture and tack location". The Astrophysical Journal. 821 (2): 75. arXiv: 1603.01009 . Bibcode:2016ApJ...821...75B. doi: 10.3847/0004-637X/821/2/75 . S2CID   119207767.
  10. ↑ Masset, F.; Snellgrove, M. (2001). "Reversing type II migration: Resonance trapping of a lighter giant protoplanet". Monthly Notices of the Royal Astronomical Society . 320 (4): L55–L59. arXiv: astro-ph/0003421 . Bibcode:2001MNRAS.320L..55M. doi: 10.1046/j.1365-8711.2001.04159.x . S2CID   119442503.
  11. 1 2 3 4 5 6 7 D'Angelo, G.; Marzari, F. (2012). "Outward Migration of Jupiter and Saturn in Evolved Gaseous Disks". The Astrophysical Journal. 757 (1): 50 (23 pp.). arXiv: 1207.2737 . Bibcode:2012ApJ...757...50D. doi:10.1088/0004-637X/757/1/50. S2CID   118587166.
  12. ↑ Pierens, A.; Raymond, S.N. (2011). "Two phase, inward-then-outward migration of Jupiter and Saturn in the gaseous solar nebula". Astronomy & Astrophysics. 533: A131. arXiv: 1107.5656 . Bibcode:2011A&A...533A.131P. doi:10.1051/0004-6361/201117451. S2CID   67818537.
  13. ↑ Raymond, Sean N.; O'Brien, David P.; Morbidelli, Alessandro; Kaib, Nathan A. (2009). "Building the terrestrial planets: Constrained accretion in the inner Solar System". Icarus . 203 (2): 644–662. arXiv: 0905.3750 . Bibcode:2009Icar..203..644R. doi:10.1016/j.icarus.2009.05.016. S2CID   15578957.
  14. ↑ Lichtenberg, Tim (2 November 2015). "Ripping apart asteroids to account for Earth's strangeness". Astrobites . Retrieved 6 November 2015.
  15. ↑ Carter, Philip J.; Leinhardt, Zoë M.; Elliott, Tim; Walter, Michael J.; Stewart, Sarah T. (2015). "Compositional evolution during rocky protoplanet accretion". The Astrophysical Journal . 813 (1): 72. arXiv: 1509.07504 . Bibcode:2015ApJ...813...72C. doi:10.1088/0004-637X/813/1/72. S2CID   53354566.
  16. 1 2 Walsh, Kevin. "The Grand Tack". Southwest Research Institute. Retrieved 6 November 2015.
  17. ↑ Jacobson, S. A.; Morbidelli, A., A. (2014). "Lunar and terrestrial planet formation in the Grand Tack scenario". Phil. Trans. R. Soc. A. 372 (2024): 174. arXiv: 1406.2697 . Bibcode:2014RSPTA.37230174J. doi:10.1098/rsta.2013.0174. PMC   4128261 . PMID   25114304.
  18. ↑ Hansen, Brad M.S. (2009). "Formation of the Terrestrial planets from a narrow annulus". The Astrophysical Journal. 703 (1): 1131–1140. arXiv: 0908.0743 . Bibcode:2009ApJ...703.1131H. doi:10.1088/0004-637X/703/1/1131. S2CID   14226690.
  19. ↑ Davidsson, Dr. Björn J. R. (9 March 2014). "Mysteries of the asteroid belt". The History of the Solar System. Retrieved 7 November 2015.
  20. ↑ Raymond, Sean (2 August 2013). "The Grand Tack". PlanetPlanet. Retrieved 7 November 2015.
  21. ↑ Deienno, Rogerio; Gomes, Rodney S.; Walsh, Kevin J.; Morbidelli, Alessandro; Nesvorný, David (2016). "Is the Grand Tack model compatible with the orbital distribution of main belt asteroids?". Icarus. 272: 114–124. arXiv: 1701.02775 . Bibcode:2016Icar..272..114D. doi:10.1016/j.icarus.2016.02.043. S2CID   119054790.
  22. ↑ O'Brien, David P.; Walsh, Kevin J.; Morbidelli, Alessandro; Raymond, Sean N.; Mandell, Avi M. (2014). "Water delivery and giant impacts in the 'Grand Tack' scenario". Icarus. 239: 74–84. arXiv: 1407.3290 . Bibcode:2014Icar..239...74O. doi:10.1016/j.icarus.2014.05.009. S2CID   51737711.
  23. ↑ Matsumura, Soko; Brasser, Ramon; Ida, Shigeru (2016). "Effects of Dynamical Evolution of Giant Planets on the Delivery of Atmophile Elements during Terrestrial Planet Formation". The Astrophysical Journal. 818 (1): 15. arXiv: 1512.08182 . Bibcode:2016ApJ...818...15M. doi: 10.3847/0004-637X/818/1/15 . S2CID   119205579.
  24. ↑ Batygin, Konstantin; Laughlin, Greg (2015). "Jupiter's decisive role in the inner Solar System's early evolution". Proceedings of the National Academy of Sciences . 112 (14): 4214–4217. arXiv: 1503.06945 . Bibcode:2015PNAS..112.4214B. doi: 10.1073/pnas.1423252112 . PMC   4394287 . PMID   25831540.
  25. ↑ University of California Santa Cruz Press Release. "Wandering Jupiter swept away super-Earths, creating our unusual Solar System". Astronomy Now . Pole Star Publications Ltd. Retrieved 3 November 2015.
  26. 1 2 Raymond, Sean N.; Izidoro, Andre; Bitsch, Bertram; Jacobsen, Seth A. (2016). "Did Jupiter's core form in the innermost parts of the Sun's protoplanetary disc?". Monthly Notices of the Royal Astronomical Society. 458 (3): 2962–2972. arXiv: 1602.06573 . Bibcode:2016MNRAS.458.2962R. doi: 10.1093/mnras/stw431 .
  27. ↑ Spaulding, Christopher (2018). "The Primordial Solar Wind as a Sculptor of Terrestrial Planet Formation". The Astrophysical Journal Letters. 869 (1): L17. arXiv: 1811.11697 . Bibcode:2018ApJ...869L..17S. doi: 10.3847/2041-8213/aaf478 . S2CID   119382211.
  28. ↑ Clement, Matthew S.; Kaib, Nathan A.; Raymond, Sean N.; Chambers, John E.; Walsh, Kevin J. (2019). "The early instability scenario: Terrestrial planet formation during the giant planet instability, and the effect of collisional fragmentation". Icarus. 321: 778–790. arXiv: 1812.07590 . Bibcode:2019Icar..321..778C. doi:10.1016/j.icarus.2018.12.033. S2CID   119063847.
  29. ↑ Johnson, B. C.; Walsh, K. J.; Minton, D. A.; Krot, A. N.; Levison, H. F. (2016). "Timing of the formation and migration of giant planets as constrained by CB chondrites". Science Advances. 2 (12): e1601658. Bibcode:2016SciA....2E1658J. doi:10.1126/sciadv.1601658. PMC   5148210 . PMID   27957541.
  30. ↑ Heller, R.; Marleau, G.-D; Pudritz, R. E. (2015). "The formation of the Galilean moons and Titan in the Grand Tack scenario". Astronomy & Astrophysics. 579: L4. arXiv: 1506.01024 . Bibcode:2015A&A...579L...4H. doi:10.1051/0004-6361/201526348. S2CID   119211657.
  31. ↑ Wilson, David (9 June 2015). "Hold on to Your Moons! Ice, Atmospheres and the Grand Tack". astrobites. Retrieved 20 November 2016.
  32. ↑ Hansen, Bradley M. S. (2018). "A dynamical context for the origin of Phobos and Deimos". Monthly Notices of the Royal Astronomical Society. 475 (2): 2452–2466. arXiv: 1801.07775 . Bibcode:2018MNRAS.475.2452H. doi: 10.1093/mnras/stx3361 .
  33. ↑ Brasser, R.; Mojzsis, S. J.; Matsumura, S.; Ida, S. (2017). "The cool and distant formation of Mars". Earth and Planetary Science Letters. 468: 85–93. arXiv: 1704.00184 . Bibcode:2017E&PSL.468...85B. doi:10.1016/j.epsl.2017.04.005. S2CID   15171917.
  34. ↑ Sumner, Thomas (5 May 2017). "Mars may not have been born alongside the other rocky planets". Science News. Retrieved 23 June 2017.
  35. ↑ Chametla, Raul O. (2020). "Capture and migration of Jupiter and Saturn in mean motion resonance in a gaseous protoplanetary disc". Monthly Notices of the Royal Astronomical Society. 492 (4): 6007–6018. arXiv: 2001.09235 . doi: 10.1093/mnras/staa260 .
  36. ↑ Griveaud, P.; Crida A.; Lega E. (2023). "Migration of pairs of giant planets in low-viscosity discs". Astronomy & Astrophysics. 672: A190. arXiv: 2303.04652 . Bibcode:2023A&A...672A.190G. doi:10.1051/0004-6361/202245208.
  37. 1 2 Pierens, Arnaud; Raymond, Sean N.; Nesvorny, David; Morbidelli, Alessandro (2014). "Outward Migration of Jupiter and Saturn in 3:2 or 2:1 Resonance in Radiative Disks: Implications for the Grand Tack and Nice models". The Astrophysical Journal Letters. 795 (1): L11. arXiv: 1410.0543 . Bibcode:2014ApJ...795L..11P. doi:10.1088/2041-8205/795/1/L11. S2CID   118417097.
  38. ↑ Marzari, F.; D’Angelo, G.; Picogna, G. (2019). "Circumstellar Dust Distribution in Systems with Two Planets in Resonance". The Astronomical Journal. 157 (2): id. 45 (12 pp.). arXiv: 1812.07698 . Bibcode:2019AJ....157...45M. doi: 10.3847/1538-3881/aaf3b6 . S2CID   119454927.
  39. ↑ D'Angelo, G.; Marzari, F. (2015). "Sustained Accretion on Gas Giants Surrounded by Low-Turbulence Circumplanetary Disks". American Astronomical Society, DPS Meeting #47. id.418.06: 418.06. Bibcode:2015DPS....4741806D.
  40. ↑ Marzari, F.; D'Angelo, G. (2013). "Mass Growth and Evolution of Giant Planets on Resonant Orbits". American Astronomical Society, DPS Meeting #45. id.113.04: 113.04. Bibcode:2013DPS....4511304M.
  41. ↑ Chambers, J. E. (2013). "Late-stage planetary accretion including hit-and-run collisions and fragmentation". Icarus. 224 (1): 43–56. Bibcode:2013Icar..224...43C. doi:10.1016/j.icarus.2013.02.015.
  42. ↑ Fischer, R. A.; Ciesla, F. J. (2014). "Dynamics of the terrestrial planets from a large number of N-body simulations". Earth and Planetary Science Letters . 392: 28–38. Bibcode:2014E&PSL.392...28F. doi:10.1016/j.epsl.2014.02.011.
  43. ↑ Barclay, Thomas; Quintana, Elisa V. (2015). "In-situ Formation of Mars-like Planets – Results from Hundreds of N-body Simulations That Include Collisional Fragmentaion". American Astronomical Society, DPS Meeting #47. #507.06: 507.06. Bibcode:2015DPS....4750706B.
  44. ↑ Izidoro, André; Raymond, Sean N.; Morbidelli, Alessandro; Winter, Othon C. (2015). "Terrestrial planet formation constrained by Mars and the structure of the asteroid belt". Monthly Notices of the Royal Astronomical Society. 453 (4): 3619–3634. arXiv: 1508.01365 . Bibcode:2015MNRAS.453.3619I. doi: 10.1093/mnras/stv1835 . hdl:11449/177633.
  45. ↑ Drążkowska, J.; Alibert, Y.; Moore, B. (2016). "Close-in planetesimal formation by pile-up of drifting pebbles". Astronomy & Astrophysics. 594: A105. arXiv: 1607.05734 . Bibcode:2016A&A...594A.105D. doi:10.1051/0004-6361/201628983. S2CID   55846864.
  46. ↑ Clement, Matthew S.; Kaib, Nathan A.; Raymond, Sean N.; Walsh, Kevin J. (2018). "Mars' Growth Stunted by an Early Giant Planet Instability". Icarus. 311: 340–356. arXiv: 1804.04233 . Bibcode:2018Icar..311..340C. doi:10.1016/j.icarus.2018.04.008. S2CID   53070809.
  47. ↑ Raymond, Sean (29 May 2018). "Mars' growth stunted!". planetplanet. Retrieved 31 January 2019.
  48. ↑ "Scientists predict that rocky planets formed from "pebbles"". Southwest Research Institute. 26 October 2015. Retrieved 22 November 2015.
  49. ↑ Levison, Harold F.; Kretke, Katherine A.; Walsh, Kevin; Bottke, William (2015). "Growing the terrestrial planets from the gradual accumulation of sub-meter sized objects". PNAS. 112 (46): 14180–14185. arXiv: 1510.02095 . Bibcode:2015PNAS..11214180L. doi: 10.1073/pnas.1513364112 . PMC   4655528 . PMID   26512109.
  50. 1 2 M. Brož, M.; Chrenko, O.; Nesvorný, D.; Dauphas, N. (2021). "Early terrestrial planet formation by torque-driven convergent migration of planetary embryos". Nature Astronomy. 5 (9): 898–902. arXiv: 2109.11385 . Bibcode:2021NatAs...5..898B. doi:10.1038/s41550-021-01383-3. S2CID   236317507.
  51. ↑ Bromley, Benjamin C.; Kenyon, Scott J. (2017). "Terrestrial planet formation: Dynamical shake-up and the low mass of Mars". The Astronomical Journal. 153 (5): 216. arXiv: 1703.10618 . Bibcode:2017AJ....153..216B. doi: 10.3847/1538-3881/aa6aaa . S2CID   119446914.
  52. ↑ Raymond, Sean N.; Izidoro, Andre (2017). "Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion". Icarus. 297: 134–148. arXiv: 1707.01234 . Bibcode:2017Icar..297..134R. doi:10.1016/j.icarus.2017.06.030. S2CID   119031134.
  53. ↑ Raymond, Sean N.; Izidoro, Andre (2017). "The empty primordial asteroid belt". Science Advances. 3 (9): e1701138. arXiv: 1709.04242 . Bibcode:2017SciA....3E1138R. doi:10.1126/sciadv.1701138. PMC   5597311 . PMID   28924609.
  54. ↑ Raymond, Sean (13 September 2017). "The asteroid belt: a cosmic refugee camp?". planetplanet. Retrieved 14 September 2017.
  55. ↑ Raymond, Sean (5 July 2017). "Where did Earth's (and the asteroid belt's) water come from?". planetplanet. Retrieved 7 July 2017.
  56. ↑ Izidoro, Andre; Raymond, Sean N.; Pierens, Arnaud; Morbidelli, Alessandro; Winter, Othon C.; Nesvorny, David (2016). "The Asteroid Belt as a Relic From a Chaotic Early Solar System". The Astrophysical Journal Letters. 833 (1): 40. arXiv: 1609.04970 . Bibcode:2016ApJ...833...40I. doi: 10.3847/1538-4357/833/1/40 . S2CID   118486946.
  57. ↑ Lichtenberg, Tim (November 2016). "Modest chaos in the early solar system". astrobites. Retrieved 21 November 2016.
  58. ↑ Deienno, Rogerio; Izidoro, Andre; Morbidelli, Alessandro; Gomes, Rodney S.; Nesvorny, David; Raymond, Sean N. (2018). "The excitation of a primordial cold asteroid belt as an outcome of the planetary instability". The Astrophysical Journal. 864 (1): 50. arXiv: 1808.00609 . Bibcode:2018ApJ...864...50D. doi: 10.3847/1538-4357/aad55d . S2CID   118947612.
  59. ↑ Clement, Matthew S.; Raymond, Sean N.; Kaib, Nathan A. (2019). "Excitation and Depletion of the Asteroid Belt in the Early Instability Scenario". The Astronomical Journal. 157 (1): 38. arXiv: 1811.07916 . Bibcode:2019AJ....157...38C. doi: 10.3847/1538-3881/aaf21e . S2CID   119495020.
  60. ↑ Zheng, Xiaochen; Lin, Douglas N. C.; Kouwenhoven, M. B. N. (2017). "Planetesimal Clearing and Size-dependent Asteroid Retention by Secular Resonance Sweeping during the Depletion of the Solar Nebula". The Astrophysical Journal. 836 (2): 207. arXiv: 1610.09670 . Bibcode:2017ApJ...836..207Z. doi: 10.3847/1538-4357/836/2/207 . S2CID   119260501.
  61. ↑ Raymond, Sean (21 February 2016). "Did the Solar System form inside-out?". PlanetPlanet. Retrieved 23 February 2016.
  62. ↑ Ogihara, Masahiro; Kobayashi, Hiroshi; Inutsuka, Shu-ichiro; Suzuki, Takeru K. (2015). "Formation of terrestrial planets in disks evolving via disk winds and implications for the origin of the solar system's terrestrial planets". Astronomy & Astrophysics. 579: A65. arXiv: 1505.01086 . Bibcode:2015A&A...579A..65O. doi:10.1051/0004-6361/201525636. S2CID   119110384.
  63. ↑ Ogihara, Masahiro; Kokubo, Eiichiro; Suzuki, Takeru K.; Morbidelli, Alessandro (2018). "Formation of the terrestrial planets in the solar system around 1 au via radial concentration of planetesimals". Astronomy & Astrophysics. 612: L5. arXiv: 1804.02361 . Bibcode:2018A&A...612L...5O. doi:10.1051/0004-6361/201832654. S2CID   54494720.
  64. ↑ Redd, Nola Taylor. "Mercury Sole Survivor of Close Orbiting Planets". Astrobiology Magazine. Retrieved 14 January 2017.
  65. ↑ Volk, Kathryn; Gladman, Brett (2015). "Consolidating and Crushing Exoplanets: Did It Happen Here?". The Astrophysical Journal Letters. 806 (2): L26. arXiv: 1502.06558 . Bibcode:2015ApJ...806L..26V. doi:10.1088/2041-8205/806/2/L26. S2CID   118052299.
  66. ↑ Morbidelli, A.; Bitsch, B.; Crida, A.; Gounelle, M.; Guillot, T.; Jacobsen, S.; Johansen, A.; Lambrechts, M.; Lega, E. (2016). "Fossilized condensation lines in the Solar System protoplanetary disk". Icarus. 267: 368–376. arXiv: 1511.06556 . Bibcode:2016Icar..267..368M. doi:10.1016/j.icarus.2015.11.027. S2CID   54642403.
  67. ↑ Hammer, Michael (12 August 2016). "Why is Mercury so far from the Sun?". astrobites. Retrieved 29 November 2016.
  68. ↑ Simon, Jacob (2016). "The Influence of Magnetic Field Geometry on the Formation of Close-in Exoplanets". The Astrophysical Journal Letters. 827 (2): L37. arXiv: 1608.00573 . Bibcode:2016ApJ...827L..37S. doi: 10.3847/2041-8205/827/2/L37 . S2CID   118420788.
  69. ↑ Lambrechts, Michiel; Morbidelli, Alessandro; Jacobson, Seth A.; Johansen, Anders; Bitsch, Bertram; Izidoro, Andre; Raymond, Sean N. (2019). "Formation of planetary systems by pebble accretion and migration: How the radial pebble flux determines a terrestrial-planet or super-Earth growth mode". Astronomy & Astrophysics. A83: 627. arXiv: 1902.08694 . Bibcode:2019A&A...627A..83L. doi:10.1051/0004-6361/201834229. S2CID   119470314.
  70. ↑ Cedenblad, Lukas; Schaffer, Noemi; Johansen, Anders; Mehlig, B.; Mitra, Dhrubaditya (2021). "Planetesimals on Eccentric Orbits Erode Rapidly". The Astrophysical Journal. 921 (2): 123. arXiv: 2011.14431 . Bibcode:2021ApJ...921..123C. doi: 10.3847/1538-4357/ac1e88 . S2CID   238227254.
  71. ↑ Clement, Matthew S.; Chambers, John E.; Jackson, Alan P. (2021). "Dynamical Avenues for Mercury's Origin. I. The Lone Survivor of a Primordial Generation of Short-period Protoplanets". The Astronomical Journal. 161 (5): 240. arXiv: 2104.11246 . Bibcode:2021AJ....161..240C. doi: 10.3847/1538-3881/abf09f . S2CID   233387902.
  72. ↑ Clement, Matthew S.; Chamber, John E. (2021). "Dynamical Avenues for Mercury's Origin. II. In Situ Formation in the Inner Terrestrial Disk". The Astronomical Journal. 162 (1): 3. arXiv: 2104.11252 . Bibcode:2021AJ....162....3C. doi: 10.3847/1538-3881/abfb6c . S2CID   233388200.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.