scholarly journals Planetesimal formation in turbulent circumstellar disks

2010 ◽  
Vol 6 (S276) ◽  
pp. 434-435
Author(s):  
David Kirsh ◽  
Ralph Pudritz
Keyword(s):  
Solar System ◽  
Gravitational Collapse ◽  
Planet Formation ◽  
Circumstellar Disks ◽  
Circumstellar Gas ◽  
Embedded Particles ◽  
Gas Drag

AbstractPlanetesimal formation occurs early in the evolution of a solar system, embedded in the circumstellar gas disk, and it is the crucial first step in planet formation. Their growth is difficult beyond boulder size, and likely proceeds via the accumulation of many rocks in turbulence followed by gravitational collapse - a process we are only beginning to understand. We have performed global simulations of the gas disk with embedded particles in the FLASH code. Particles and gas feel drag based on differential velocities and densities. Grains and boulders of various sizes have been investigated, from micron to km, with the goal of understanding where in the disk large planetesimals will tend to form, what sizes will result, and what size ranges of grains will be preferentially incorporated. We have so far simulated particles vertical settling and radial drift under the influence of gas drag, and their accumulations in turbulent clumps.

scholarly journals Giant planet formation — a theoretical timeline

2004 ◽  
Vol 202 ◽  
pp. 167-174 ◽  
Author(s):  
Günther Wuchterl
Keyword(s):  
Star Formation ◽  
Solar System ◽  
Formation Process ◽  
Planet Formation ◽  
Giant Planet ◽  
Circumstellar Disks ◽  
Giant Planets ◽  
Low Mass ◽  
Star Formation Regions ◽  
Observational Techniques

Low mass circumstellar disks are a result of the star formation process. The growth of dust and solid planets in such pre-planetary disks determines many properties of our solar system. Models of the Solar System giant planets indicate an enrichment of heavy elements and imply heavy element cores. Detailed models therefore describe giant planet formation as a consequence of the formation of solid planets that have grown sufficiently large to permanently bind gas from the protoplanetary nebula. The diversity of Solar System and extrasolar giant planets is explained by variations in the core growth rates caused by a coupling of the dynamics of planetesimals and the contraction of the massive envelopes they dive into, as well as by changes in the hydrodynamical accretion behavior of the envelopes resulting from differences in nebula density, temperature and orbital distance. Detailed formation models are able to determine observables as luminosities, radii and effective temperatures of young giant planets. Present observational techniques do now allow to probe star formation regions at ages covering all evolutionary stages of the giant planet formation process.

scholarly journals Terrestrial planet formation in extra-solar planetary systems

2007 ◽  
Vol 3 (S249) ◽  
pp. 233-250 ◽  
Author(s):  
Sean N. Raymond
Keyword(s):  
Final Stage ◽  
Planet Formation ◽  
Giant Planet ◽  
Terrestrial Planet ◽  
Circumstellar Disks ◽  
Giant Planets ◽  
Terrestrial Planets ◽  
Low Mass Stars ◽  
Low Mass ◽  
Rocky Planets

AbstractTerrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, “hot Jupiter” systems are likely to also contain exterior, very water-rich Earth-like planets, and also “hot Earths”, very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.

scholarly journals Probing AU-scale Structure using Spectro-astrometry

2004 ◽  
Vol 221 ◽  
pp. 417-424 ◽  
Author(s):  
Michihiro Takami ◽  
Jeremy Bailey ◽  
Antonio Chrysostomou ◽  
Motohide Tamura ◽  
Hiroshi Terada
Keyword(s):  
Adaptive Optics ◽  
Main Sequence ◽  
Planet Formation ◽  
Hubble Space Telescope ◽  
Circumstellar Disks ◽  
Scale Structure ◽  
Young Stars ◽  
Space Telescope ◽  
Powerful Technique ◽  
Circumstellar Environment

The circumstellar environment within 10 AU of young stars are of particular interest for star and planet formation. Unfortunately, present imaging facilities such as the Hubble Space Telescope or adaptive optics on 10-m telescopes cannot resolve this region. We have proved that “spectro-astrometry” is a powerful technique for discovering pre-main-sequence binaries, determining kinematics of outflows and providing evidence for gaps in circumstellar disks — all down to AU scales. In this paper, we summarise our progress to date.

scholarly journals Dust Around Young Stars: How Related to Solar System Dust?

1995 ◽  
Vol 10 ◽  
pp. 351-392 ◽  
Author(s):  
Martha S. Hanner
Keyword(s):  
Solar System ◽  
Interplanetary Space ◽  
Circumstellar Disks ◽  
Theoretical Work ◽  
Interplanetary Dust ◽  
Young Stars ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Technical Advances ◽  
Dust Disks

Study of the dust in circumstellar disks around young stars is currently an extremely active area in astronomy. There is little doubt that accretion disks are a natural part of protostellar evolution. Much recent observational and theoretical work is giving us a clearer picture of the physical conditions in dust disks and their evolutionary progression. IRAS observations revealed that many main-sequence stars, such as p Pictoris, have circumstellar disks. But whether these disks are related to planetary formation is not yet understood.A portion of the dust in disks around young stars ultimately may be incorporated into planetary systems. Thus, study of the dust in our own solar system complements the remote sensing of protostellar regions and aids in reconstructing the evolutionary history of the dust. Since comets formed in the cold outer regions of the solar nebula, they may contain intact interstellar grains. As the comets lose material during passage through the warm inner solar system, some of these grains will be released into interplanetary space. Technical advances now allow analysis of individual micrometer or smaller grains in interplanetary dust particles and primitive meteorite samples. Isotopic anomalies and patterns of crystal growth in these particles are yielding tantalizing clues about the interstellar material incorporated into these solar system samples.

scholarly journals Jupiter’s decisive role in the inner Solar System’s early evolution

2015 ◽  
Vol 112 (14) ◽  
pp. 4214-4217 ◽  
Author(s):  
Konstantin Batygin ◽  
Greg Laughlin
Keyword(s):  
Solar System ◽  
Dynamical Evolution ◽  
Decisive Role ◽  
Terrestrial Planets ◽  
The Sun ◽  
Mean Motion Resonances ◽  
The Earth ◽  
Short Period ◽  
Orbital Periods ◽  
Gas Drag

The statistics of extrasolar planetary systems indicate that the default mode of planet formation generates planets with orbital periods shorter than 100 days and masses substantially exceeding that of the Earth. When viewed in this context, the Solar System is unusual. Here, we present simulations which show that a popular formation scenario for Jupiter and Saturn, in which Jupiter migrates inward from a > 5 astronomical units (AU) to a ≈ 1.5 AU before reversing direction, can explain the low overall mass of the Solar System’s terrestrial planets, as well as the absence of planets with a < 0.4 AU. Jupiter’s inward migration entrained s ≳ 10−100 km planetesimals into low-order mean motion resonances, shepherding and exciting their orbits. The resulting collisional cascade generated a planetesimal disk that, evolving under gas drag, would have driven any preexisting short-period planets into the Sun. In this scenario, the Solar System’s terrestrial planets formed from gas-starved mass-depleted debris that remained after the primary period of dynamical evolution.

scholarly journals Circumstellar disks in high-mass star environments: the early solar system

2009 ◽  
Vol 5 (H15) ◽  
pp. 746-747
Author(s):  
Thierry Montmerle ◽  
Matthieu Gounelle ◽  
Georges Meynet
Keyword(s):  
Solar System ◽  
Circumstellar Disks ◽  
Energetic Particles ◽  
High Mass ◽  
Circumstellar Disk ◽  
Mass Star ◽  
Early Solar System ◽  
Explosive Nucleosynthesis ◽  
By Products

AbstractThe early solar system represents the only case we have of a circumstellar disk that can be investigated “in situ” -albeit 4.6 Gyr after its formation. Meteorites studies give mounting evidence for an intense irradiation phase of the young circumsolar disk by energetic particles, and also for contamination by products of high-mass stellar and/or explosive nucleosynthesis. We thus discuss the conditions of the birth of the solar system in a high-mass star environment.

scholarly journals A First Look at the Disk Population in the Auriga-California Molecular Cloud

2013 ◽  
Vol 8 (S299) ◽  
pp. 151-152
Author(s):  
Hannah Broekhoven-Fiene ◽  
Brenda C. Matthews ◽  
Paul M. Harvey ◽  
Keyword(s):  
Grain Growth ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Planet Formation ◽  
Circumstellar Disks ◽  
The Other ◽  
Giant Molecular Clouds ◽  
Formation Potential

AbstractThe Auriga-California Molecular Cloud (AMC) is one of two nearby (within 500 pc) giant molecular clouds, the other being the Orion A Molecular Cloud (OMC). We aim to study the properties of circumstellar disks in the AMC to compare the planet formation potential and processes within the AMC to those for other clouds. A first look with measurements from Spitzer observations suggests that AMC disk properties, such as the distribution of disk luminosities and the evolution of the mid-IR excesses, are not vastly different from those in other regions. Follow-up observations in the submm, mm and cm can be used to measure disk masses and the degree of grain growth from spectral slopes to more completely characterize the disk population.

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