III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape

H. Stellar Planetary Systems: A Stochastic Profusion of Galaxies, Solar Orrerys, and Habitable Zones

Drazkowska, Joanna, et al. Planet Formation in the Era of ALMA and Kepler: From Peebles to Exoplanets. arXiv:2203.09759. In a paper for Protostars and Planets VII, astronomers in Germany, Sweden, Chile, Taiwan, Israel, China, the USA, and France (Alessandro Morbidelli) provide the latest comprehensive survey from our home base of how an ever increasing array of diverse exoworlds might have been formed.

. In this chapter, we summarize the new information derived from the exoplanets population and the circumstellar disks observations. We present the new developments in planet formation theory, from dust evolution to the growth of planetary cores by accretion of planetesimals, pebbles, and gas. We review the state-of-the-art models for the formation of diverse planetary systems, including the population synthesis approach which is necessary to compare theoretical model outcomes to the exoplanet population. In addition, there is growing evidence that the first planetary cores start forming early, during the circumstellar disk buildup process. (Excerpt)

Dvorak, Rudolf, ed. Extrasolar Planets: Formation, Detection, and Dynamics. Weinheim: WILEY-VCH Verlag, 2008. Akin to current Deeg and Mason works posted here, technical papers on all such aspects as Earthkind begins to scan the celestial horizons for other worlds.

Elkins-Tanton, Linda and Benjamin Weiss, eds. Planetesimals: Early Differentiation and Consequences for Planets. Cambridge: Cambridge University Press, 2017. The editors are the Director of the School of Earth and Space Exploration at Arizona State University, and the Chair of the Program in Planetary Sciences at MIT. As collaborative humankinder proceeds to reconstruct how exoworlds and this home Earth came to form from such seed-like origins, this volume covers their Dynamical Evolution, Chemical and Mineralogical Diversity, Asteroids as Records of Formation and Differentiation, and Early Differentiation and Consequences for Planet Formation. Ought we to then wonder, what global sapient faculty rises out of such a vicarious ancestry to achieve cosmic self-retrospective?

Processes governing the evolution of planetesimals are critical to understanding how rocky planets are formed, how water is delivered to them, the origin of planetary atmospheres, how cores and magnetic dynamos develop, and ultimately, which planets have the potential to be habitable. Theoretical advances and new data from asteroid and meteorite observations, coupled with spacecraft missions such as Rosetta and Dawn, have led to major advances in this field over the last decade. This transdisciplinary volume presents an authoritative overview of the latest in our understanding of the processes of planet formation. Combining meteorite, asteroid and icy body observations with theory and modelling of accretion and orbital dynamics, this text also provides insights into the exoplanetary system and the search for habitable worlds. This is an essential reference for those interested in planetary formation, solar system dynamics, exoplanets and planetary habitability. (Summary)

Elser, Sebastian, et al. How Common are Earth-Moon Planetary Systems? Icarus. 214/2, 2011. In Rare Earth (2000) Peter Ward and Donald Brownlee say that a planet with a large moon is helpful for life to evolve, but worry that the system would be statistically unusual. Drawing on a decade of celestial advances, University of Zurich and University of Colorado astrophysicists now contend that such couplings are much more common. Indeed, along with many other findings, the Ward and Brownlee case has been largely refuted. On the contrary, our galaxy and the whole cosmos seems made to innately seed itself with conducive bioearths.

The Earth’s comparatively massive moon, formed via a giant impact on the proto-Earth, has played an important role in the development of life on our planet, both in the history and strength of the ocean tides and in stabilizing the chaotic spin of our planet. Here we show that massive moons orbiting terrestrial planets are not rare. A large set of simulations by Morishima et al. (Morishima, R., Stadel, J., Moore, B. [2010]. Icarus. 207, 517–535), where Earth-like planets in the habitable zone form, provides the raw simulation data for our study. We use limits on the collision parameters that may guarantee the formation of a circumplanetary disk after a protoplanet collision that could form a satellite and study the collision history and the long term evolution of the satellites qualitatively. We find that giant impacts with the required energy and orbital parameters for producing a binary planetary system do occur with more than 1 in 12 terrestrial planets hosting a massive moon, with a low-end estimate of 1 in 45 and a high-end estimate of 1 in 4. (Abstract, 357)

Emsenhuber, Alexandr, Alexandre, et al. Planetary Population Synthesis and the Emergence of Four Classes of Planetary System Architectures. arXiv:2303.00012. We note this work by Ludwig-Maximilians-Universit, University of Bern, and MPI Astronomie exo-researchers as another example of new perceptions of how solar systems seem to have an array of overall properties.

Here, we review the population synthesis method to explore which conditions lead to different planetary system architectures. As a result, we identify four main groups: a near-in situ compositionally ordered terrestrial and ice planets, migrated sub-Neptunes, mixed low-mass and dynamically active giants without inner low-mass planets. These four classes exhibit typical formation pathways and are certain mass scales. The breakdown into classes allows to better understand which physical processes are dominant. Comparison with observations reveals certain differences to the actual population, pointing at limitation of theoretical understanding. (Excerpt)

Faridani, Thea, et al. More Likely Than You Think: Inclination-Driving Secular Resonances are Common in Known Exoplanet Systems.. arXiv:2406.09359.. We cite this work by UCLA, Georgia Tech and Yale University astroscientists as another current perception of solar systems as a whole interactive entity wherein planetary locations and transits influence each other. See also The PLATO Mission at arXiv:2406.05447 for another version.

Multi-planet systems face significant challenges to detection. One mechanism to excite mutual inclination between planets is secular resonance, where the nodal precession frequencies align such as to increase the efficiency of angular momentum transport between them. In this work, we explore known three-planet systems, determine whether they are in (or were in) secular resonance due to evolving stellar oblateness, and demonstrate the implications of resonance on their detectability and stability. We show that about 20% of three planet transiting systems seem to undergo these resonances early in their lives. (Excerpt)

Fields, Benjamin, et al. Information Gain as a Tool for Assessing Biosignature Missions. International Journal of Astrobiology. July, 2023. Blue Marble Space Institute of Science researchers BF, Sohom Gupta and McCullen Sandora propose a better, systematic approach as we Earthlings embark on a near and farther celestial census to bravely seek out, evaluate potential neighbors. Hello. is anyone there?

We propose the mathematical notion of information gain as a way to best assess the value of biosignature searches. This approach applies to many case examples: the minimal number of samples to see a trend in signal occurrence rate as a function of an environmental variable, and how much cost to allocate to aspect; false positives and false negatives, tradeoffs between resolution and coverage; how to deduce a habitability boundary; and much more. In each case, we state quantitative, optimum recommendations for mission design, selection, and/or target choice. (Excerpt)

Blue Marble Space Institute is an international community based in Seattle engaged in building a sustainable future guided by scientific knowledge. Our mission is to explore life as a universal phenomenon. We publish in academic journals, and through seminar series as well as the SAGANet social network. We pursue aspects such as: How did life on Earth originate, How does human civilization and the Earth system co-evolve and How unique is Earth among other planets in the galaxy.

Fischer, Debra. Early Start for Rocky Planets. Nature. 486/331, 2012. The Yale University astronomer reviews a Letter in this issue “An Abundance of Small Exoplanets around Stars with a Wide Range of Metallicities” by Lars Buchhave, et al, a large team from Copenhagen, NASA and California. They find the chemical composition of stars which host smaller planets to be more varied than those with larger planets. This result is seen to favor an earlier start and prevalence for more earth-like worlds.

Fisher, Theresa, et al.. A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life-As-We-Know-It. arXiv:2310.05359. Arizona State University astrobiologists TF, Estelle Janin and Sara Walker post a latest comprehensive review as Earthumanity prepares to seek and rightly identify near and further occasions of inhabited exoworlds. A segment wonders over how to evaluate what evolutionary stage they may have reached, with attention to global civilizations. The especial contribution herein is a novel notice of life’s multiplex anatomy and physiology as vital indicators. See also PyATMOS: A Scalable Grid of Hypothetical Planetary Atmospheres by Aditya Chopra, et al at 2308.10624; and Fully fluorinated non-carbon compounds NF3 and SF6 as technosignature gases by Sara Seager, et al at 2308.13667 for other studies.

The near-term capability to characterize terrestrial exoplanet atmospheres may bring us closer to discovering alien life. However, detectable candidate biosignature gases are subject to false positives that can be produced abiotically. To distinguish, we take a complex systems approach using a chemical reaction network analysis of planetary atmospheres. Network properties like mean degree and shortest path length can effectively display when CH4 is produced from methanogenesis and serpentinization. Our results confirm how a network theoretic approach can clearly specify biological, abiotic and anomalous atmospheres. (Excerpt)

Beyond the implications for biosignature detection, the influence of biology on atmospheric reaction networks may provide a window into the physics of life itself. If there is a ‘universal biology’ dictated by the physical constraints of the universe, one manifestation may be in its network topology. For instance, one might model planetary evolution as a multilayer network, where each layer represents the chemistry in the geosphere, biosphere, or atmosphere and technosphere. In any case, further investigation into atmospheric reaction networks is warranted in a variety of fields of exoplanet science and astrobiology. (16)

Folger, Tim. The Planet Boom. Discovery. May, 2011. One of many post-Kepler satellite reports trying to convey this awesome discovery of an innately world-seeding, gravid cosmos. Per the quote, our earth can be known as far from rare. By any measure galaxies will be filled with solar systems, which seem to proliferate in every imaginable variety. And as Bill Borucki, for many years NASA’s champion of the Kepler mission, comments, this fantastic vista brings a profound significance to earth’s stirring ability via humankind to learn and decide to succeed.

For the first time, we have a handle on the odds, and the numbers beaming in from Kepler are not only encouraging but staggering. “Our galaxy contains 200 billion stars,” (Geoffrey) Marcy says, “I would guess that at least 30 percent of them have an earth-size planet. So 30 percent of 200 billion, that’s at least 60 billion Earth-size planets just in our galaxy alone.” (33)

Franck, Siegfried, et al. Extraterrestrial Gaias. Schneider, Stephen, et al, eds. Scientists Debate Gaia. Cambridge: MIT Press, 2004. The detection of extrasolar, earth-like planets takes on a new dimension when viewed through the lens of the Gaia perspective. Whether they are life-bearing can be ascertained by the composition of their atmosphere.

The general question is whether an Earth-sized planet discovered outside the solar system can accommodate a self-regulating geosphere-biosphere system with homeorrhesis (i.e., sister of Gaia). (315)

Frank, Adam. How Nature Builds a Planet. Discover. July, 2005. The latest info on varieties of planetary formation as an intelligent earth learns about its own origin and those of its neighbors.

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