This page intentionally left blank PLANET FORMATION Theory, Observations, and Experiments It is just over ten years since the first planet outside our Solar System was detected Since then, much work has been done to try to understand how extrasolar planets may form This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our Solar System in particular Drawing from recent advances in observational, experimental, and theoretical research, it summarizes our current understanding of the planet formation processes, and addresses major open questions and research issues Chapters are written by leading experts in the field of planet formation and extrasolar planet studies The book is based on a meeting held in 2004 at Ringberg Castle in Bavaria, where experts gathered together to present and exchange their ideas and findings It is a comprehensive resource for graduate students and researchers, and is written to be accessible to newcomers to the field The Cambridge Astrobiology series aims to facilitate the communication of recent advances in astrobiology, and to foster the development of scientists conversant in the wide array of disciplines needed to carry astrobiology forward Books in the series are at a level suitable for graduate students and researchers, and are written to be accessible to scientists working outside the specific area covered by the book Hubert Klahr and Wolfgang Brandner are both at the Max-PlanckInstitute for Astronomy in Heidelberg Hubert Klahr is Head of the Theory Group for Planet and Star Formation, and Wolfgang Brandner is a staff researcher and Head of the Adaptive Optics Lab Cambridge Astrobiology Series Editors Bruce Jakosky, Alan Boss, Frances Westall, Daniel Prieur, and Charles Cockell Books in the series: Planet Formation: Theory, Observations, and Experiments Edited by Hubert Klahr and Wolfgang Brandner ISBN-10 0-521-86015-6 ISBN-13 978-0-521-86015-4 PLANET FORMATION Theory, Observations, and Experiments Edited by HUBERT KLAHR Max-Planck-Institut făur Astronomie, Heidelberg, Germany WOLFGANG BRANDNER Max-Planck-Institut făur Astronomie, Heidelberg, Germany cambridge university press Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge cb2 2ru, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521860154 © Cambridge University Press 2006 This publication is in copyright Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press First published in print format 2006 isbn-13 isbn-10 978-0-511-22008-1 eBook (EBL) 0-511-22008-1 eBook (EBL) isbn-13 isbn-10 978-0-521-86015-4 hardback 0-521-86015-6 hardback Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate Dedicated to the one and only true planet formation specialist Slartibartfast of Magrathea and his father D N Adams Contents Preface Acknowledgments Historical notes on planet formation Peter Bodenheimer 1.1 Introduction 1.2 Descartes and von Weizsăacker: vortices 1.3 Magnetic effects 1.4 Gravitational instability 1.5 Core accretion: gas capture 1.6 Planet searches The Formation and Evolution of Planetary Systems: placing our Solar System in context Jeroen Bouwman, Michael R Meyer, Jinyoung Serena Kim, Murray D Silverstone, John M Carpenter, and Dean C Hines 2.1 Introduction 2.1.1 The formation of planets: from protoplanetary towards debris disk systems 2.1.2 The Spitzer Space Telescope and the formation and evolution of planetary systems legacy program 2.2 From protoplanetary to debris disks: processing and dispersion of the inner dust disk 2.3 Debris disks: Asteroid or Kuiper Belt? Destruction of protoplanetary disks by photoevaporation Sabine Richling, David Hollenbach and Harold W Yorke 3.1 Introduction 3.2 Photoevaporation and other dispersal mechanisms 3.3 Photoevaporation by external radiation 3.4 Photoevaporation by the central star vii page xiii xv 1 14 14 16 17 20 25 31 31 33 34 36 Contents viii 3.5 3.6 Photoevaporation and dust evolution Conclusions Acknowledgments Turbulence in protoplanetary accretion disks: driving mechanisms and role in planet formation Hubert Klahr, Michal Rozyczka, Natalia Dziourkevitch, Richard Wăunsch, and Anders Johansen 4.1 Introduction 4.1.1 Protostellar collapse and formation of disks 4.1.2 Observations of accretion in protoplanetary systems 4.1.3 Self-gravity and the early evolution of disks 4.1.4 Viscous evolution 4.2 Magnetohydrodynamic turbulence 4.2.1 Non-ideal magnetohydrodynamics 4.2.2 Ohmic dissipation 4.2.3 Ambipolar diffusion 4.2.4 Hall term 4.3 Layered accretion 4.3.1 Ionization structure 4.3.2 Layered disk evolution 4.4 Alternative instabilities in the dead zone 4.5 Transport by turbulence 4.5.1 Dust dynamics 4.5.2 Dust-trapping mechanisms 4.5.3 Turbulent diffusion 4.6 Conclusions The origin of solids in the early Solar System Mario Trieloff and Herbert Palme 5.1 Introduction: geoscience meets astronomy 5.2 Meteorites: remnants of planetesimal formation 4.6 billion years ago in the asteroid belt 5.3 Calcium-aluminum-rich inclusions and chondrules: remnants from the earliest Solar System 5.4 Compositional variety of chondrites: planetesimal formation occurred at a variety of conditions in the protoplanetary disk 5.4.1 Metal abundance and oxidation state 5.4.2 Ratio of refractory to volatile elements 5.4.3 Major element fractionations: Mg, Si, Fe 5.4.4 Oxygen isotopes 39 40 41 42 42 42 43 44 46 47 48 50 50 50 51 52 55 56 57 58 59 61 62 64 64 66 67 69 69 73 74 74 ... and Charles Cockell Books in the series: Planet Formation: Theory, Observations, and Experiments Edited by Hubert Klahr and Wolfgang Brandner ISBN-10 0-521-86015-6 ISBN-13 978-0-521-86015-4 PLANET. .. United States of America by Cambridge University Press, New York www .cambridge. org Information on this title: www .cambridge. org/9780521860154 © Cambridge University Press 2006 This publication is... Theory, Observation, and Experiments, ed Hubert Klahr and Wolfgang Brandner Published by Cambridge University Press C Cambridge University Press 2006 Peter Bodenheimer “ the extremely large space