III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape
H. Prolific ExoWorlds, Galactic Dynamics, Solar Orrerys, Habitable Zones, Biosignatures
Kempton, Eliza. Window on a Watery World. Nature. 513/493, 2014. A report on Water Vapour Absorption in the Clear Atmosphere of a Neptune-sized Exoplanet by Jonathan Fraine, et al, in the same issue. While many exoworlds are cloud-covered, for the first time a candidate, HAT-P-11b, has been found which is cloud free so as to allow spectrum analysis of its surface composition. In this case, water molecules have been detected as a good sign that this crucial media for evolving life is widely prevalent.
Kipping, David. Do Planets Remember How They Formed?. arXiv:1709.04987. As a fresh galactic and cosmic expanse becomes prolifically filled with planetary and solar phenomena, our Earthly exploration is entering a new era of quantifying, cataloging, and explaining. Here a Columbia University astronomer (view website) considers entropic histories as a novel way to retrace their evolution. One result is that Extrasolar planetary systems reveal a rich diversity of architectures, most of which do not directly resemble our own by way of planet-metallicities, mutual inclinations, orbital eccentricities, host star correlations, and more.
One of the most directly observable features of a transiting multi-planet system is their size-ordering when ranked in orbital separation. Kepler has revealed a rich diversity of outcomes, from perfectly ordered systems, like Kepler-80, to ostensibly disordered systems, like Kepler-20. Under the hypothesis that systems are born via preferred formation pathways, one might reasonably expect non-random size-orderings reflecting these processes. However, subsequent dynamical evolution, often chaotic and turbulent in nature, may erode this information and so here we ask - do systems remember how they formed? To address this, we devise a model to define the entropy of a planetary system's size-ordering, by first comparing differences between neighboring planets and then extending to accommodate differences across the chain. We find that the observed Kepler multis display a highly significant deficit in entropy compared to a randomly generated population. Put together, our work establishes that Kepler systems do indeed remember something of their younger years and highlights the value of information theory for exoplanetary science. (Abstract excerpts)
Knezevic, Zoran and Andrea Milani, eds.
Dynamics of Populations of Planetary Systems.
Cambridge: Cambridge University Press,
Proceedings of an IAU Colloquium held in Belgrade, September 2004, noted as an example of our breakthrough ability to detect extrasolar systems and planets – then some 150, by November 2008 over 300 of all kinds and sizes. Surely an earthwide, collaborative endeavor as we instrument and scan the skies with an intuition of a life-conducive cosmos filled with neighbors and cousins.
Knezevic, Zoran and Anne Lemaitre, eds. Complex Planetary Systems. Cambridge: Cambridge University Press, 2015. This volume 310 in the International Astronomical Union IAU symposium series contributes to the nascent scientific project to explore a novel profligate universe which seeds and fills itself with all manner of potentially life-bearing orbital worlds. Typical papers are Dynamic Study of Possible Host Stars for Extrasolar Planetary Systems and The Grand Tack Model: A Critical Review.
IAU Symposium 310 takes a broad look at the complexity of planetary systems, in terms of the formation and dynamical evolution of planets, their satellites, minor bodies and space debris, as well as to the habitability of exoplanets, in order to understand and model their physical processes. The main topics covered are diverse, including: studies of the rotation of planets and satellites, including their internal structures; the long term evolution of space debris and satellites; planetary and satellite migration mechanisms; and the role of the Yarkovsky effect on the evolution of the rotating small bodies. Intended for researchers and advanced students studying complex planetary systems, IAU S310 appeals to non-specialists interested in problems such as the habitability of exoplanets, planetary migration in the early Solar System, or the determination of chaotic orbits.
Kouvenhoven, M. B. N, et al. Planetary Systems in Star Clusters. arXiv:1609.00898. After two decades of scientific realizations of a radically different cosmos that fills itself with planetary objects of all manner of types, sizes and stellar locales, a team of astrophysicists with joint Chinese and Dutch postings add another observation of how our own sun system is uniquely special. Most stars, as also galaxies, actually tend to collect and bunch together, so that planets in these jumbled environs are not in circular orbits but “scatter and disperse” widely.
Thousands of confirmed and candidate exoplanets have been identified in recent years. Consequently, theoretical research on the formation and dynamical evolution of planetary systems has seen a boost, and the processes of planet-planet scattering, secular evolution, and interaction between planets and gas/debris disks have been well-studied. Almost all of this work has focused on the formation and evolution of isolated planetary systems, and neglect the effect of external influences, such as the gravitational interaction with neighbouring stars. Most stars, however, form in clustered environments that either quickly disperse, or evolve into open clusters. Under these conditions, young planetary systems experience frequent close encounters with other stars, at least during the first 1-10 Myr, which affects planets orbiting at any period range, as well as their debris structures. (Abstract)
Kovacs, Tamas. Recurrence Network Analysis of Exoplanetary Observables. . We cite this entry by an Eotvos University, Budapest physicist as an example of how network complexity researchers are beginning to detect and quantify an intrinsic, independent, self-organizing mathematics which seems to apply even to the cosmic realm of dynamic solar systems.
Recent advancements of complex network representation among several disciplines motivated the investigation of exoplanetary dynamics by means of recurrence networks. We are able to recover different dynamical regimes by means of various network measures obtained from synthetic time series of a model planetary system. The framework of complex networks is also applied to real astronomical observations acquired by recent state-of-the-art surveys. The outcome of the analysis is consistent with earlier studies opening new directions to investigate planetary dynamics.
Krommydas, Dimitrios and Fabio Scardigli. Exponential Distance Relation (aka Titus-Bose law) in Extra Solar Planetary Systems. arXiv:2307.06070. Into this year, Leiden University astronomers provide further perception of an overall mathematical basis which seems to characterize and arrange an entire solar orrery system. These findings are a result of the 21th century scientific revolution as myriad systems become known and quantified. So one more intrinsic celestial orderliness, as intimated long ago, gains credible proof. At what point and agency might we altogether realize a phenomenal procreation?
In this paper we present phenomenal evidence for a valid exponential distance relation (also known as the Titius-Bode law) in 32 subject planetary systems with 5 planets or more. Our basis is the semi-log fittings of data findings, which are then compared with 4000 theoretic systems created at random. In this way, possible chance origins are ruled out. We review Harmonic Resonances and match up with the Titius-Bode method so to altogether conclude that such a scalar arrangement has a strongly corroborated presence in solar systems. Further, it appears as the most economical fitting law for the description of spacing among planetary orbits. (Abstract)
Lammer, Helmut. Origin and Evolution of Planetary Atmospheres: Implications for Habitability. Heidelberg: Springer, 2013. At the outset, it is worth notice that studies of this vast scale go on at all, unimaginable a decade ago, as a global civilization begins to learn about a fertile cosmos filled with neighbor bioworlds. An Austrian Academy of Sciences, Space Research Institute, astrophysicist, drawing upon an international collaboration, can describe the “physics and chemistry of planetary protoatmosphere formation and composition.” Might one add as if the phenomenal way a certain genesis universe tries to describe, understand, and create itself? See also the copious article “What Makes a Planet Habitable?” by Lammer, et al below.
Figure 1: Illustration of Earth-analogue class I, Martian-type class II, Icy moon-type classes III and IV and Water world class V habitats. Class I habitats represent planetary bodies on which stellar and geophysical conditions allow Earth-analogue planets to evolve so that complex multicellular life forms may originate and inhabit the planets hydrosphere, surface and subsurface environments. (x)
Lammer, Helmut and Maxim Khodachenko, eds. Characterizing Stellar and Exoplanetary Environments. Berlin: Springer, 2015. As the synopsis notes, this volume edited by Austrian Space Research Institute scientists expands the human horizon to a deeply welcoming cosmos spacescape. A closing chapter is Living with Stars: Future Space-Based Exoplanet Search and Characterization Missions.
In this book an international group of specialists discusses studies of exoplanets subjected to extreme stellar radiation and plasma conditions. It is shown that such studies will help us to understand how terrestrial planets and their atmospheres, including the early Venus, Earth and Mars, evolved during the host star’s active early phase. The book presents an analysis of findings from Hubble Space Telescope observations of transiting exoplanets, as well as applications of advanced numerical models for characterizing the upper atmosphere structure and stellar environments of exoplanets. The book is divided into four main parts, grouping chapters on exoplanet host star radiation and plasma environments, exoplanet upper atmosphere and environment observations, exoplanet and stellar magnetospheres, and exoplanet observation and characterization. The book closes with an outlook on the future of this research field.
Lammer, Helmut, et al. What Makes a Planet Habitable? Astronomy and Astrophysics Review. 17/2, 2009. Some 15 senior members of the European astrospace community from Austria, Germany, France, Holland, Sweden, England, and onto Russia and the US, provide an extensive review of a galaxy and cosmos seemingly rift with worlds of every kind, as the Abstract notes. As these many studies express, an innately conducive milieu of solar systems, suitable biospheres, earth-analogs, seems increasingly evident. The paper agrees that life’s origin requires the common minimum of a membrane vesicle, metabolic proteins, and an information carrier, along with a driving energy gradient.
This work reviews factors which are important for the evolution of habitable Earth-like planets such as the effects of the host star dependent radiation and particle fluxes on the evolution of atmospheres and initial water inventories. We discuss the geodynamical and geophysical environments which are necessary for planets where plate tectonics remain active over geological time scales and for planets which evolve to one-plate planets. A classification of four habitat types is proposed. Class I habitats represent bodies on which stellar and geophysical conditions allow Earth-analog planets to evolve so that complex multi-cellular life forms may originate. Class II habitats includes bodies on which life may evolve but due to stellar and geophysical conditions that are different from the class I habitats, the planets rather evolve toward Venus- or Mars-type worlds where complex life-forms may not develop. Class III habitats are planetary bodies where subsurface water oceans exist which interact directly with a silicate-rich core, while class IV habitats have liquid water layers between two ice layers, or liquids above ice. Furthermore, we discuss from the present viewpoint how life may have originated on early Earth, the possibilities that life may evolve on such Earth-like bodies and how future space missions may discover manifestations of extraterrestrial life. (Abstract)
Laughlin, Gregory and Jack Lissauer. Exoplanetary Geophysics: An Emerging Discipline. Schubert, Gerald, ed.. Treatise on Geophysics. Amsterdam: Elsevier, 2015. A chapter for this 11 volume, 2nd edition by UC Santa Cruz, and NASA Ames scientists as terrestrial studies can now be extended to a galactic and cosmic scale. Who are we Earthlings to be the universe's way of describing and comprehending itself?
Lemonick, Michael. Can We Find Another Earth? Discover. March, 2002. The rapid progress in detecting stars with orbiting planets by perturbations in their movement due to the orbiting bodies, now over 100, leads to plans for telescopes able to focus in from Jupiter to Earth size globes.