Copyrighted Material http://exoplanets.co/ This is the free sample version of the book Exoplanets and Alien Solar Systems by Dr. Tahir Yaqoob, and is not for sale. The material is pro- tected by copyright law. Note that the full version of the book contains a comprehensive section of annotated notes expanding on footnote super- scripts in the main text, and the Notes section is not shown in the sample version. The full version of the 252-page book is available from most online book retailers, and it is also available in Kindle and Nook e-Book formats. Some hyperlinks are given below for retailers that stock the book, and for free reading apps for the electronic versions of the book. Some retailers for the paperback version (ISBN: 978-0-9741689-2-0): Amazon.com, and Amazon sites in: UK – Canada – France – Germany – Spain – Italy – Japan – Barnes and Noble (bn.com), The Book Depository (bookdepository.com). Note that the Book De- pository offers free worldwide shipping. The Kindle version is available from the book’s Kindle page at Amazon.com, and Amazon sites in: UK – France – Germany – Spain – Italy – You don’t need a Kindle to read the Kindle book, because with Ama- zon’s free Kindle reading apps, you can read the book on your computer (PC or Mac), on the iPad, as well as on several types of phone (iPhone, Blackberry, Android, Windows Phone 7). Don’t forget that you can also read Kindle eBooks right in your browser, thanks to the Kindle Cloud Reader technology. The Nook version is available from the book’s Nook page at bn.com. You don’t need a Nook to read the Nook eBook because you can get a free Nook reading app for a number of devices, including your computer. You may also be interested in free articles on exoplanets on the blog: http://exoplanetsdigest.com. Review Snippets “In this book, Dr. Yaqoob takes the reader to a journey of recent dis- coveries. He is able to translate complex subjects and techniques using a very simple language and make those more accessible to the general audience.” “The author talks to the reader and keeps the reader wanting more and more. It was hard to avoid flipping fast to the next page and see what was next.” Prof. D. F. de Mello, Washington, D.C. “The author’s approach to each subject indicates a savvy for the teach- ing process. The material is well organized into sections and the book overall is not tedious on the eye, in fact at times I didn’t want to put it down.” Dave Reneke, writer for Australasian Science magazine. (See full review at Dave Reneke’s website, http://www.davidreneke.com/.) Some snippets from reviews at amazon.com (go to the book’s reviews page at amazon.com to read all the reviews): “This book reviews the ’state of the art’ of exoplanet research. The material spans not only the details of known exoplanet systems, but also the methods used for exoplanet detection and explains a lot of the science behind it all.” “The material is well-organized and the book is thorough, without ever being tedious or confusing.” “Exoplanets and Alien Solar Systems is a book not only about extra- solar planets but also about our own solar system and our presence in the Universe.” Exoplanets and Alien Solar Systems Tahir Yaqoob, Ph.D. Copyright c 2011 Tahir Yaqoob. All rights reserved. Front cover image courtesy nasaimages.org. Cover design, copyright c 2011 Tahir Yaqoob. TM A publication of New Earth Labs (Education and Outreach), P. O. Box 5672, Baltimore, MD 21210. http://www.newearthlabs.com. Further information and updates on Exoplanets and Alien Solar Systems can be found at http://exoplanets.co. Also by the same author: What Can I Do to Help My Child with Math When I Don't Know Any Myself? Available in eBook and paperback formats. http://helpyourchildwithmath.com. No part of this book may be reproduced, translated, distributed, transmit- ted, or stored in a retrieval system, by any means whatsoever, without the permission of the copyright holder. Brief excerpts (totaling less than one page) may be quoted in literary review articles without permission. The author’s opinions and statements made in this work are associated with the author alone, and are not endorsed by any institution that the author is affiliated with, nor any institution that is mentioned in this work. Exoplanets and Alien Solar Systems is also available in paperback for- mat (ISBN: 978-0-9741689-2-0) from most online book stores. It is also available in other eBook formats: see http://exoplanets.co/exoplanets-book.html. Cataloging data: Exoplanets and Alien Solar Systems. Tahir Yaqoob. Includes index. Keywords: 1. Exoplanets; 2. Extrasolar planets; 3. Astronomy; 4. Astrophysics; 5. Physics; 6. Space Science; 7. Planetary Science. Contents 1 Stepping Out 1 Connecting with a Conversation Through History . 1 Exoplanets Reveal Themselves . 3 Jupiter’s Compelling Attraction . 5 2 A Sketch of the New Science 9 Chapter Overview . 9 Near and Far . 10 Solar System Overview . 12 Why Are Some Objects Known as “Candidate” Planets? 21 How Many Exoplanets and Alien Solar Systems Have Been Found? . 24 Why Don’t Exoplanets Have Names? . 25 What Do We Want to Know About Exoplanets and Why? 27 How Far Away Are the Discovered Planets? . 32 How Many Alien Moons Have Been Discovered? . 34 Are There Exoplanets That Are Not Associated with a Star? . 35 How Can I Get the Latest Updates on Exoplanets and Alien Solar Systems? . 37 3 How It’s Done 39 The Host Stars . 39 v How are Exoplanets Discovered? . 45 Timing Method . 46 Doppler-Shift Method . 48 Astrometry . 52 Transit Method . 54 Gravitational Microlensing Method . 57 Direct Imaging . 59 What Can We Actually Measure? . 62 Oblique, Retrograde, and Eccentric Orbits . 67 Chemical Composition . 68 Groundbased versus Spacebased Observations . 72 The CoRoT Mission . 73 The Kepler Mission . 74 When Was the First Exoplanet Discovered? . 76 4 The Discoveries 77 Exoplanet Types . 77 Demographics . 81 The Alien Solar Systems . 83 Masses of the Exoplanets . 84 Exoplanet Sizes . 86 Living Close to a Star . 93 Orbital Period and Size . 107 Exoplanet Eccentricities . 114 Is Our Solar System Typical? . 116 Planet Formation and Migration . 117 How Common are Planets around Stars? . 133 Correlation of Planet Incidence with Heavy Element Abundance . 135 Multiplanet Systems . 137 A Summary of the Important Findings So Far . 138 vi Tentative Results from the Kepler Candidates Sample . 141 5 Where Is Everyone? 145 What Is Life? . 145 The Origin of Life . 146 Challenges for the Origin of Life on Earth . 160 Chemistry for Life: What’s the Deal with Arsenic? . 167 Water in the Moon . 168 The Problem of Volatile Delivery . 170 Exoplanet Climatology and Habitable Zones . 171 The Host Star, Tidal Locking, and System Stability . 172 Temperature and Albedo . 174 Exoplanet Atmospheres . 177 Climate Solutions . 180 The Faint Young Sun Problem . 181 Circumstellar Habitable Zone . 183 Galactic Habitable Zone . 186 Is There a New Answer to the Old Question? . 187 How Long Would It Take to Get to the Nearest Exoplanet?191 Ant School . 193 A What Is a Planet? 195 Does the Classification of a Solar System Object De- pend on How It Was Formed? . 198 What Are the Mass Limits for a Planet? . 198 So What Is an Exoplanet? . 200 B Selected Websites 203 Notes 207 Index 235 vii Chapter 1 Stepping Out Connecting with a Conversation Through History Whatever you were doing before reading this, take your mind away from it, and imagine that you are outside,Material barefoot on a peb- bly beach, looking out at the vibrant blue ocean in front of you. It’s slightly chilly. Feel the cool wind running against your face. Breathe in and smell the rawness of the Earth around you. Clouds move out of the way and the warmth of the Sun caresses your face. Hear the relentless but soothing rhythm of the wavy water. Feel the hard stone under your feet. Your eyes feast on the view of the blue abyss in front of you. You are being nurtured from head to toe. But you are standing on a planet that is hurtling through an unfor- giving vacuum at an unimaginable speed of over 60; 000 miles per hour (about 100; 000 kilometers per hour). Yet you stand peace- fully as one, with this colossal ball of rock and water that protects you and gives you life. Up in the sky rages a hydrogen furnace Copyrightedof incredible dimensions, that has faithfully served your planet for five billion years, so that it may give you life. In the modern trappings of existence it is so easy to forget that you live on a planet. Just beyond home is an environment that is so lethal that it’s hard to believe the picture described above could ex- 1 ist. Cosmic rays that could devastate your atomic make up. Elec- tric and magnetic fields that could instantly put your lights out. X-rays and other radiation that could fry you in an instant. Tem- peratures so cold that you would shatter into a billion fragments. A vacuum that would suck the life out of you. All of this is not very far away. Yet you can stand on your planet, look around at the beauty that cocoons you, and feel like you are the most fortunate being in the Universe. In this book we will connect with a conversation that has perme- ated humanity throughout history. A conversation that is the man- ifestation of a collective consciousness that goes back to a time before we even knew what a planet was, before we knew how to make fire, all the way back to whenever self-awareness arose.