Host Stars and their Effects on Exoplanet Atmospheres - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Host Stars and their Effects on Exoplanet Atmospheres write by Jeffrey Linsky. This book was released on 2019-05-23. Host Stars and their Effects on Exoplanet Atmospheres available in PDF, EPUB and Kindle. Like planets in our solar system, exoplanets form, evolve, and interact with their host stars in many ways. As exoplanets acquire material and grow to the final size, their atmospheres are subjected to intense UV and X-radiation and high-energy particle bombardment from the young host star. Whether a planet can retain its atmosphere and the conditions for significant mass loss both depend upon the strength of the host star's high-energy radiation and wind, the distance of the exoplanet from its host star, the gravitational potential of the exoplanet, and the initial chemical composition of the exoplanet atmosphere. This introductory overview describes the physical processes responsible for the emission of radiation and acceleration of winds of host stars that together control the environment of an exoplanet, focusing on topics that are critically important for understanding exoplanetary atmospheres but are usually not posed from the perspective of host stars. Accordingly, both host stars and exoplanets are not studied in isolation but are treated as integrated systems. Stellar magnetic fields, which are the energy source for activity phenomena including high-energy radiation and winds, play a critical role in determining whether exoplanets are habitable. This text is primarily for researchers and graduate students who are studying exoplanet atmospheres and habitability, but who may not have a background in the physics and phenomenology of host stars that provide the environment in which exoplanets evolve. It provides a comprehensive overview of this broad topic rather than going deeply into many technical aspects but includes a large list of references to guide those interested in pursuing these questions. Nonspecialists with a scientific background should also find this text a valuable resource for understanding the critical issues of contemporary exoplanet research.
The Effects of Stellar Magnetic Activity and Variability on Observations of Exoplanets
The Effects of Stellar Magnetic Activity and Variability on Observations of Exoplanets - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook The Effects of Stellar Magnetic Activity and Variability on Observations of Exoplanets write by Brett M. Morris. This book was released on 2019. The Effects of Stellar Magnetic Activity and Variability on Observations of Exoplanets available in PDF, EPUB and Kindle. The search for life in the Universe outside of the Solar System focuses on the study of potentially habitable exoplanets. Exoplanets have been discovered principally via the transit method, which reveals planetary radii and orbital periods, among other things. In transiting multi-planet systems, we can measure the masses of exoplanets without expensive spectroscopy by using transit timing variations. The orbit of a single transiting planet around a single star would be (nearly) perfectly periodic, but if there's more than one planet in the system, the gravitational influence of each planet on each other changes the orbital shape and orientation. The apparent variation in the exoplanet transit times thus transmits information about the mass and orbit of the perturbing planet. Transits can also reveal the composition of exoplanet atmospheres via transmission spectroscopy. When the planet passes in front of the host star, it will appear largest at wavelengths where the planet's atmosphere is opaque, and smallest at wavelengths where the atmosphere is transparent. Thus by measuring the apparent radius of the planet as a function of wavelength, we can obtain a spectrum of an exoplanet's atmosphere. However, there are additional signals generated by magnetic activity and variability at the stellar surface which inject confounding time- and wavelength-dependent signals into the spectrophotometry of exoplanet host stars which complicate all of the aforementioned measurements. We must understand heterogeneous stellar surfaces in order to accurately answer astrobiological questions such as: does this planet have a surface, and what is the composition of its atmosphere? The goal of this dissertation is to explore stellar magnetic activity and variability and their impacts on measurements of exoplanets with implications for astrobiology. I used the transiting planet HAT-P-11 b to measure the size and latitude distributions of starspots on its active K4 dwarf host star, to find that its magnetic activity mirrors the Sun's. I measured the chromospheric activity of HAT-P-11 and compared it to stars of similar temperature and rotation period to find that it's the most active of its peers, perhaps suggestive of star-planet interaction. I directly measured starspot coverage on a sample of bright stars via TiO molecular band modeling. I identified the possibility of detecting stellar activity cycles of nearby stars using precision astrometry. I devised a technique for measuring robust exoplanet radii even in the presence of significant starspot distributions by reparameterizing the transit light curve of Mandel & Agol (2002). Finally, I devised a simulator for James Webb Space Telescope observations of transiting exoplanets, to explore the limits imposed by stellar magnetic activity on transit timing and transmission spectroscopy measurements for three systems with potentially habitable exoplanets.
Exoplanet Atmospheres
Exoplanet Atmospheres - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Exoplanet Atmospheres write by Sara Seager. This book was released on 2010-08-02. Exoplanet Atmospheres available in PDF, EPUB and Kindle. Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introduction, examples that combine the relevant physics equations with real data, and exercises. Topics range from foundational knowledge, such as the origin of atmospheric composition and planetary spectra, to more advanced concepts, such as solutions to the radiative transfer equation, polarization, and molecular and condensate opacities. Since planets vary widely in their atmospheric properties, Seager emphasizes the major physical processes that govern all planetary atmospheres. Moving from first principles to cutting-edge research, Exoplanet Atmospheres is an ideal resource for students and researchers in astronomy and earth sciences, one that will help prepare them for the next generation of planetary science. The first textbook to describe exoplanet atmospheres Illustrates concepts using examples grounded in real data Provides a step-by-step guide to understanding the structure and emergent spectrum of a planetary atmosphere Includes exercises for students
Exoplanet Science Strategy
Exoplanet Science Strategy - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Exoplanet Science Strategy write by National Academies of Sciences, Engineering, and Medicine. This book was released on 2019-01-17. Exoplanet Science Strategy available in PDF, EPUB and Kindle. The past decade has delivered remarkable discoveries in the study of exoplanets. Hand-in-hand with these advances, a theoretical understanding of the myriad of processes that dictate the formation and evolution of planets has matured, spurred on by the avalanche of unexpected discoveries. Appreciation of the factors that make a planet hospitable to life has grown in sophistication, as has understanding of the context for biosignatures, the remotely detectable aspects of a planet's atmosphere or surface that reveal the presence of life. Exoplanet Science Strategy highlights strategic priorities for large, coordinated efforts that will support the scientific goals of the broad exoplanet science community. This report outlines a strategic plan that will answer lingering questions through a combination of large, ambitious community-supported efforts and support for diverse, creative, community-driven investigator research.
Solar-Terrestrial Environmental Prediction
Solar-Terrestrial Environmental Prediction - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Solar-Terrestrial Environmental Prediction write by Kanya Kusano. This book was released on 2023-01-31. Solar-Terrestrial Environmental Prediction available in PDF, EPUB and Kindle. Powerful solar explosions, such as flares and coronal mass ejections, greatly disturb the electromagnetic environment around the Earth and the atmosphere. They may even impact various social systems—communications, positioning, electric power supply, aviation and activities in space. Such variations in the space environment, which can influence human activities, are called “space weather.” The space weather disaster caused by a solar explosion is a potential risk in modern society. To reduce and mitigate space weather impacts, it is essential to understand the structure and dynamics of the solar–terrestrial environment and to predict the variations. This book comprehensively describes space weather, from the basics of related sciences to the possible social impacts. It was compiled based on a national research project on solar–terrestrial environment prediction conducted in Japan recently. It consists of four parts: the linkage between space weather and society; the magnetosphere of the Earth and space weather prediction; solar storms and space weather prediction; and long-term prediction of solar cycle activity and climate impacts. Each chapter covers the basics and applications of each area, which helps readers gain a broad understanding of the subject matter throughout the book. In addition, readers are able to select and read the topics they are most interested in. It is especially valuable for undergraduate and graduate students and young researchers studying space weather and related topics, and is further helpful for experts in various industries related to space weather disasters. The translation was done with the help of artificial intelligence (machine translation by the service DeepL.com). The present version has been revised technically and linguistically by the authors in collaboration with a professional translator.
