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.

4. What are planets made of?

2021 ◽  
pp. 47-75
Author(s):  
Raymond T. Pierrehumbert
Keyword(s):  
Life Cycle ◽  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Big Bang ◽  
Heavy Elements ◽  
Milky Way Galaxy ◽  
First Stars ◽  
The Big Bang ◽  
The Universe

‘What are planets made of?’ assesses what planets are made of, beginning by looking at the life cycle of stars, and the kinds of stars which populate the Universe. Although the first stars of the Universe could not have formed planetary systems, the process did not take long to get under way. The Milky Way galaxy formed not long after the Big Bang and has been building its stock of heavy elements ever since. Thus, our Solar System incorporates ingredients from a mix of myriad expired stars, most of which have been processed multiple times through short-lived stars.

scholarly journals Surveys for Metal-Poor Stars in the Galaxy: A New Window on the Low-Abundance Universe

1998 ◽  
Vol 11 (1) ◽  
pp. 58-61
Author(s):  
T.C. Beers
Keyword(s):  
Milky Way ◽  
High Signal ◽  
Signal To Noise ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
History Of ◽  
Chemical History ◽  
Low Metallicity ◽  
New Generation ◽  
The Universe

Measurement of the abundances of the light and heavy elements in stars of the Milky Way galaxy is the cornerstone for the study of numerous aspects of chemical evolution in galaxies and the Universe. We stand poised to enter an era of rapid understanding, as new-generation telescopes with apertures in the 8m-10m class enable astronomers to obtain high-resolution, high-signal-to-noise near-UV, optical, and IR spectra of the stars which have locked up the chemical history of our Galaxy in their outer atmospheres. It is thus appropriate to review present surveys for the low-metallicity stars of our Galaxy, as the stars we uncover today will be studied so intensively in the coming decades.

1. Beginnings

2021 ◽  
pp. 1-13
Author(s):  
Raymond T. Pierrehumbert
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Solar System ◽  
Planetary Systems ◽  
Big Bang ◽  
Giant Planets ◽  
Baryonic Matter ◽  
Rocky Planets ◽  
The Big Bang ◽  
The Universe

‘Beginnings’ discusses the general processes that form planetary systems, particularly the Solar System. Most of the Universe is made of a mysterious substance called ‘dark matter’, and an even more mysterious substance called ‘dark energy’. After the birth of the Universe in the Big Bang, the tiny bits of stardust which have accumulated contain the heavier elements (baryonic matter) that make it possible to form beings like ourselves, and the planets on which we live. We mustn't forget the importance of the formation of protostars, as well as gas and ice giant planets, the evolution of the proto-Sun, and the formation of inner rocky planets.

scholarly journals Cool Jupiters greatly outnumber their toasty siblings: occurrence rates from the Anglo-Australian Planet Search

2019 ◽  
Vol 492 (1) ◽  
pp. 377-383 ◽  
Author(s):  
Robert A Wittenmyer ◽  
Songhu Wang ◽  
Jonathan Horner ◽  
R P Butler ◽  
C G Tinney ◽  
...  
Keyword(s):  
Solar System ◽  
Radial Velocity ◽  
Planetary System ◽  
Planetary Systems ◽  
Giant Planets ◽  
Occurrence Rate ◽  
Hot Jupiters ◽  
The Past ◽  
Order Of Magnitude

ABSTRACT Our understanding of planetary systems different to our own has grown dramatically in the past 30 yr. However, our efforts to ascertain the degree to which the Solar system is abnormal or unique have been hindered by the observational biases inherent to the methods that have yielded the greatest exoplanet hauls. On the basis of such surveys, one might consider our planetary system highly unusual – but the reality is that we are only now beginning to uncover the true picture. In this work, we use the full 18-yr archive of data from the Anglo-Australian Planet Search to examine the abundance of ‘cool Jupiters’ – analogues to the Solar system’s giant planets, Jupiter and Saturn. We find that such planets are intrinsically far more common through the cosmos than their siblings, the hot Jupiters. We find that the occurrence rate of such ‘cool Jupiters’ is $6.73^{+2.09}_{-1.13}$ per cent, almost an order of magnitude higher than the occurrence of hot Jupiters (at $0.84^{+0.70}_{-0.20}$ per cent). We also find that the occurrence rate of giant planets is essentially constant beyond orbital distances of ∼1 au. Our results reinforce the importance of legacy radial velocity surveys for the understanding of the Solar system’s place in the cosmos.

scholarly journals A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy

Galaxies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Xiang Cai ◽  
Jonathan H. Jiang ◽  
Kristen A. Fahy ◽  
Yuk L. Yung
Keyword(s):  
Statistical Estimation ◽  
Milky Way ◽  
Galactic Center ◽  
Model Simulation ◽  
Temporal Variations ◽  
Extraterrestrial Intelligence ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Peak Location ◽  
Intelligent Life

In the field of astrobiology, the precise location, prevalence, and age of potential extraterrestrial intelligence (ETI) have not been explicitly explored. Here, we address these inquiries using an empirical galactic simulation model to analyze the spatial–temporal variations and the prevalence of potential ETI within the Galaxy. This model estimates the occurrence of ETI, providing guidance on where to look for intelligent life in the Search for ETI (SETI) with a set of criteria, including well-established astrophysical properties of the Milky Way. Further, typically overlooked factors such as the process of abiogenesis, different evolutionary timescales, and potential self-annihilation are incorporated to explore the growth propensity of ETI. We examine three major parameters: (1) the likelihood rate of abiogenesis (λA); (2) evolutionary timescales (Tevo); and (3) probability of self-annihilation of complex life (Pann). We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life. Our model simulation also identified a peak location for ETI at an annular region approximately 4 kpc from the galactic center around 8 billion years (Gyrs), with complex life decreasing temporally and spatially from the peak point, asserting a high likelihood of intelligent life in the galactic inner disk. The simulated age distributions also suggest that most of the intelligent life in our galaxy are young, thus making observation or detection difficult.

Epilogue: Paradigms, Problems, and Predictions

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Planetary Systems ◽  
Planetary Science ◽  
Good Time ◽  
Science Program ◽  
The Galaxy ◽  
Recent Developments ◽  
Powerful Stimulus ◽  
Rapid Pace ◽  
Over Time

This concluding chapter talks about how astronomers and space agencies in dozens of countries are helping to see the solar system as never before, transforming points of light into real worlds, and even bringing samples of those worlds back to Earth. At the same time, the stunning discovery of hundreds of other planetary systems in the galaxy has provided a powerful stimulus to understand how planetary systems form and evolve, and to find out what makes one system different from another. Moreover, in 2010, NASA announced its latest science plan. One of the key goals for NASA's future planetary science program is to learn how the Sun's family began and how it has changed over time. The chapter argues that the rapid pace of recent developments makes now a good time to take stock of what scholars know, even though the story is still incomplete.

Computer Information Library Clusters

2019 ◽  
pp. 142-147
Author(s):  
Fu Yuhua
Keyword(s):  
Solar System ◽  
Social Science ◽  
Natural Science ◽  
Milky Way ◽  
Variation Principle ◽  
Unified Theory ◽  
Milky Way Galaxy ◽  
System Information ◽  
Set Up

Based on creating generalized and hybrid set and library with neutrosophy and quad-stage method, this chapter presents the concept of computer information library clusters (CILC). There are various ways and means to form CILC. For example, CILC can be considered as the “total-library” and consists of several “sub-libraries.” As another example, in CILC, a total-library can be set up, and a number of sub-libraries are side by side with the total-library. Specially, for CILC, the operation functions can be added; for example, according to natural science computer information library clusters (natural science CILC), and applying variation principle of library (or sub-library), partial and temporary unified theory of natural science so far with different degrees can be established. Referring to the concept of natural science CILC, the concepts of social science CILC, natural science and social science CILC, and the like can be presented. While referring to the concept of computer information library clusters, the concepts of computer and non-computer information library clusters, earth information library clusters, solar system information library clusters, Milky Way galaxy information library clusters, universe information library clusters, and the like can be presented.

scholarly journals No evidence for interstellar planetesimals trapped in the Solar system

2020 ◽  
Vol 497 (1) ◽  
pp. L46-L49 ◽  
Author(s):  
A Morbidelli ◽  
K Batygin ◽  
R Brasser ◽  
S N Raymond
Keyword(s):  
Solar System ◽  
Oort Cloud ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Interstellar Space ◽  
Fast Decay ◽  
Early Solar System ◽  
The Past ◽  
Solar System Bodies ◽  
Main Asteroid Belt

ABSTRACT In two recent papers published in MNRAS, Namouni and Morais claimed evidence for the interstellar origin of some small Solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined Centaurs. Here, we discuss the flaws of those papers that invalidate the authors’ conclusions. Numerical simulations backwards in time are not representative of the past evolution of real bodies. Instead, these simulations are only useful as a means to quantify the short dynamical lifetime of the considered bodies and the fast decay of their population. In light of this fast decay, if the observed bodies were the survivors of populations of objects captured from interstellar space in the early Solar system, these populations should have been implausibly large (e.g. about 10 times the current main asteroid belt population for the retrograde co-orbital of Jupiter). More likely, the observed objects are just transient members of a population that is maintained in quasi-steady state by a continuous flux of objects from some parent reservoir in the distant Solar system. We identify in the Halley-type comets and the Oort cloud the most likely sources of retrograde co-orbitals and highly inclined Centaurs.

scholarly journals On the survival of resonant and non-resonant planetary systems in star clusters

2020 ◽  
Vol 497 (2) ◽  
pp. 1807-1825
Author(s):  
Katja Stock ◽  
Maxwell X Cai ◽  
Rainer Spurzem ◽  
M B N Kouwenhoven ◽  
Simon Portegies Zwart
Keyword(s):  
Solar System ◽  
Star Clusters ◽  
Planetary Systems ◽  
Dynamical Evolution ◽  
Giant Planets ◽  
Mean Motion Resonances ◽  
Orbital Parameters ◽  
Eccentric Orbits ◽  
The Individual ◽  
Exoplanet Systems

ABSTRACT Despite the discovery of thousands of exoplanets in recent years, the number of known exoplanets in star clusters remains tiny. This may be a consequence of close stellar encounters perturbing the dynamical evolution of planetary systems in these clusters. Here, we present the results from direct N-body simulations of multiplanetary systems embedded in star clusters containing N = 8k, 16k, 32k, and 64k stars. The planetary systems, which consist of the four Solar system giant planets Jupiter, Saturn, Uranus, and Neptune, are initialized in different orbital configurations, to study the effect of the system architecture on the dynamical evolution of the entire planetary system, and on the escape rate of the individual planets. We find that the current orbital parameters of the Solar system giants (with initially circular orbits, as well as with present-day eccentricities) and a slightly more compact configuration, have a high resilience against stellar perturbations. A configuration with initial mean-motion resonances of 3:2, 3:2, and 5:4 between the planets, which is inspired by the Nice model, and for which the two outermost planets are usually ejected within the first 105 yr, is in many cases stabilized due to the removal of the resonances by external stellar perturbation and by the rapid ejection of at least one planet. Assigning all planets the same mass of 1 MJup almost equalizes the survival fractions. Our simulations reproduce the broad diversity amongst observed exoplanet systems. We find not only many very wide and/or eccentric orbits, but also a significant number of (stable) retrograde orbits.

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