scholarly journals Planetary systems formation and the diversity of extrasolar systems

2010 ◽  
Vol 6 (S276) ◽  
pp. 441-442
Author(s):  
Yamila Miguel ◽  
Octavio M. Guilera ◽  
Adrián Brunini
Keyword(s):  
Analytical Model ◽  
System Architecture ◽  
Planetary System ◽  
Initial Conditions ◽  
Planetary Systems ◽  
Large Sample ◽  
Migration Rates ◽  
Extrasolar Systems ◽  
Planetary Migration ◽  
The Universe

AbstractWith the end of answer questions as, how common are planetary systems like our own in the Universe? and What is the diversity of planetary systems that we could find in the universe?, we develop a semi-analytical model for computing planetary systems formation and consider different initial conditions for generating a large sample of planetary systems, which is analysed statistically. We explore the effects in the planetary system architecture of assuming different initial disc profiles and planetary migration rates.

scholarly journals Terrestrial planet formation in low-mass disks: dependence with initial conditions

2014 ◽  
Vol 9 (S310) ◽  
pp. 218-219
Author(s):  
M. P. Ronco ◽  
G. C. de Elía ◽  
O. M. Guilera
Keyword(s):  
Gas Phase ◽  
Analytical Model ◽  
Ad Hoc ◽  
Planet Formation ◽  
Initial Conditions ◽  
Planetary Systems ◽  
Terrestrial Planet ◽  
Initial Distribution ◽  
Protoplanetary Disk ◽  
Low Mass

AbstractIn general, most of the studies of terrestrial-type planet formation typically use ad hoc initial conditions. In this work we improved the initial conditions described in Ronco & de Elía (2014) starting with a semi-analytical model wich simulates the evolution of the protoplanetary disk during the gas phase. The results of the semi-analytical model are then used as initial conditions for the N-body simulations. We show that the planetary systems considered are not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar to those found in the previous work.

scholarly journals Will gravitational waves discover the first extra-galactic planetary system?

2020 ◽  
Vol 29 (14) ◽  
pp. 2043007
Author(s):  
Camilla Danielski ◽  
Nicola Tamanini
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Milky Way ◽  
Planetary System ◽  
Planetary Systems ◽  
System A ◽  
The Mean ◽  
Satellite Galaxies ◽  
The Universe

Gravitational waves have opened a new observational window through which some of the most exotic objects in the universe, as well as some of the secrets of gravitation itself, can now be revealed. Among all these new discoveries, we recently demonstrated15 that space-based gravitational wave observations will have the potential to detect a new population of massive circumbinary exoplanets everywhere inside our Galaxy. In this paper, we argue that these circumbinary planetary systems can also be detected outside the Milky Way, in particular within its satellite galaxies. Space-based gravitational wave observations might thus constitute the mean to detect the first extra-galactic planetary system, a target beyond the reach of standard electromagnetic searches.

Aged Stars and Disrupted Exosystems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Chemical Analysis ◽  
Scientific Community ◽  
White Dwarfs ◽  
Planetary System ◽  
Planetary Systems ◽  
Fusion Reactors ◽  
Long Time ◽  
The Dead ◽  
The Universe

Several chapters in this book illustrate the long, complex paths that the scientific community takes to uncover the workings of the Universe. This chapter focuses on the chemical analysis of stars by spectrographically unravelling their light into its constituent colors that, in retrospect, revealed the first evidence of planetary systems, although that remained unrecognized for a long time. A century ago astronomers discovered that many burned-out stars, no longer working as fusion reactors, had unexpected chemicals in their atmospheres. Now these are recognized as evaporated fragments of planetary-system bodies that came too close to the dead star and were eventually pulled into it. With aged stars first clearing their neighborhood by swelling into giants, how can it be that fragments of planetary-system bodies end up in a continuing stream of material crashing into the resulting white dwarfs, ongoing even as they are observed many millions of years after that occurred?

scholarly journals How metallicity affects volatile abundances: implications for planetary system formation

2020 ◽  
Vol 493 (1) ◽  
pp. 661-675
Author(s):  
Gerardo Dominguez
Keyword(s):  
Molecular Cloud ◽  
Interstellar Dust ◽  
Planetary System ◽  
Initial Conditions ◽  
Planetary Systems ◽  
Planetary Formation ◽  
Volatile Elements ◽  
Wide Range ◽  
Dust Grain ◽  
Numerical Treatments

ABSTRACT Astronomers have confirmed the existence of several thousand extrasolar planetary systems having a wide range of orbital and compositional characteristics. A host star’s metallicity, defined as the abundance of all elements heavier than helium (metals), appears to play a role in determining whether an exoplanetary system is more likely to include Jupiter-sized gas and ice giants. Here, we show how molecular cloud (MC) metallicity is likely to significantly affect the initial conditions of planetary formation by affecting the abundances of volatile ices (H2O, CO, etc.) in parent MCs. Through analytic and numerical treatments of molecular chemical lifetimes, we show that volatile elements are more likely to be found as ices in metal-rich clouds compared to metal-poor ones. These correlations, in turn, may impact the characteristics of planetary systems as a function of their metallicity as suggested by the systematic shifts in snowline distances as a function of metallicity. We evaluate the ‘wet Earth’ hypothesis for the origins of Earth’s water and find that elevated protoplanetary disc pressures are required to retain the required partial (∼2 per cent) monolayer of water on interstellar dust grain surfaces with MRN distribution.

scholarly journals The role of disc torques in forming resonant planetary systems

2020 ◽  
Vol 635 ◽  
pp. A204 ◽  
Author(s):  
S. Ataiee ◽  
W. Kley
Keyword(s):  
Planetary System ◽  
Planetary Systems ◽  
Accurate Method ◽  
Parameter Study ◽  
Resonant Systems ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
Planetary Migration ◽  
Self Gravity ◽  
The Impact

Context. The most accurate method for modelling planetary migration and hence the formation of resonant systems is using hydrodynamical simulations. Usually, the force (torque) acting on a planet is calculated using the forces from the gas disc and the star, while the gas accelerations are computed using the pressure gradient, the star, and the planet’s gravity, ignoring its own gravity. For a non-migrating planet the neglect of the disc gravity results in a consistent torque calculation while for a migrating case it is inconsistent. Aims. We aim to study how much this inconsistent torque calculation can affect the final configuration of a two-planet system. We focus on low-mass planets because most of the multi-planetary systems, discovered by the Kepler survey, have masses around ten Earth masses. Methods. Performing hydrodynamical simulations of planet–disc interaction, we measured the torques on non-migrating and migrating planets for various disc masses as well as density and temperature slopes with and without considering the self-gravity of the disc. Using this data, we found a relation that quantifies the inconsistency, used this relation in an N-body code, and performed an extended parameter study modelling the migration of a planetary system with different planet mass ratios and disc surface densities, to investigate the impact of the torque inconsistency on the architecture of the planetary system. Results. Not considering disc self-gravity produces an artificially larger torque on the migrating planet that can result in tighter planetary systems. The deviation of this torque from the correct value is larger in discs with steeper surface density profiles. Conclusions. In hydrodynamical modelling of multi-planetary systems, it is crucial to account for the torque correction, otherwise the results favour more packed systems. We examine two simple correction methods existing in the literature and show that they properly correct this problem.

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

scholarly journals DESTINY: Database for the Effects of STellar encounters on dIsks and plaNetary sYstems

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Asmita Bhandare ◽  
Susanne Pfalzner
Keyword(s):  
Planetary System ◽  
Planetary Systems ◽  
Gravitational Effect ◽  
Parameter Study ◽  
Orbital Inclination ◽  
Particle Properties ◽  
Disk Size ◽  
Stellar Group ◽  
Cluster Environment ◽  
Parabolic Orbits

Abstract Most stars form as part of a stellar group. These young stars are mostly surrounded by a disk from which potentially a planetary system might form. Both, the disk and later on the planetary system, may be affected by the cluster environment due to close fly-bys. The here presented database can be used to determine the gravitational effect of such fly-bys on non-viscous disks and planetary systems. The database contains data for fly-by scenarios spanning mass ratios between the perturber and host star from 0.3 to 50.0, periastron distances from 30 au to 1000 au, orbital inclination from 0∘ to 180∘ and angle of periastron of 0∘, 45∘ and 90∘. Thus covering a wide parameter space relevant for fly-bys in stellar clusters. The data can either be downloaded to perform one’s own diagnostics like for e.g. determining disk size, disk mass, etc. after specific encounters, obtain parameter dependencies or the different particle properties can be visualized interactively. Currently the database is restricted to fly-bys on parabolic orbits, but it will be extended to hyperbolic orbits in the future. All of the data from this extensive parameter study is now publicly available as DESTINY.

scholarly journals III. On the nature and construction of the sun and fixed stars

1795 ◽  
Vol 85 ◽  
pp. 46-72 ◽  
Keyword(s):  
Central Body ◽  
Planetary System ◽  
Considerable Progress ◽  
The Sun ◽  
Great Satisfaction ◽  
The Earth ◽  
The World ◽  
Celestial Bodies ◽  
The Universe ◽  
Made In

Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

Signature change in p-adic and noncommutative FRW cosmology

2014 ◽  
Vol 29 (27) ◽  
pp. 1450155 ◽  
Author(s):  
Goran S. Djordjevic ◽  
Ljubisa Nesic ◽  
Darko Radovancevic
Keyword(s):  
Loop Quantum Gravity ◽  
Initial Conditions ◽  
Planck Scale ◽  
The Other ◽  
Frw Cosmology ◽  
Signature Change ◽  
Discrete Nature ◽  
Frw Metric ◽  
The Universe ◽  
Friedmann Robertson Walker

The significant matter for the construction of the so-called no-boundary proposal is the assumption of signature transition, which has been a way to deal with the problem of initial conditions of the universe. On the other hand, results of Loop Quantum Gravity indicate that the signature change is related to the discrete nature of space at the Planck scale. Motivated by possibility of non-Archimedean and/or noncommutative structure of space–time at the Planck scale, in this work we consider the classical, p-adic and (spatial) noncommutative form of a cosmological model with Friedmann–Robertson–Walker (FRW) metric coupled with a self-interacting scalar field.

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