Skip to main content Accessibility help
×
Home
Hostname: page-component-99c86f546-md8df Total loading time: 0.281 Render date: 2021-11-27T03:39:22.518Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

10 - Accretion of planetesimals and the formation of rocky planets

Published online by Cambridge University Press:  24 February 2010

Dániel Apai
Affiliation:
Space Telescope Science Institute, Baltimore
Dante S. Lauretta
Affiliation:
University of Arizona
Get access

Summary

Abstract Here we describe the formation of rocky planets and asteroids in the context of the planetesimal hypothesis. Small dust grains in protoplanetary disks readily stick together forming millimeter-to-centimeter-sized aggregates, many of which experience brief heating episodes causing melting. Growth to kilometer-sized planetesimals might proceed via continued pairwise sticking, turbulent concentration, or gravitational instability of a thin particle layer. Gravitational interactions between planetesimals lead to rapid runaway and oligarchic growth forming lunar to Marssized protoplanets in 105 to 106 years. Giant impacts between protoplanets form Earth-mass planets in 107 to 108 years, and occasionally lead to the formation of large satellites. Protoplanets may migrate far from their formation locations due to tidal interactions with the surrounding disk. Radioactive decay and impact heating cause melting and differentiation of planetesimals and protoplanets, forming ironrich cores and silicatemantles, and leading to some loss of volatiles. Dynamical perturbations from giant planets eject most planetesimals and protoplanets from regions near orbital resonances, leading to Asteroid Belt formation. Some of this scattered material will collide with growing terrestrial planets, altering their composition as a result. Numerical simulations and radioisotope dating indicate that the terrestrial planets of the Solar System were essentially fully formed in 100–200 million years.

The formation of rocky planets marks the last stage in the evolution of a protoplanetary disk, extending beyond the dissipation of the gas disk itself. The seeds of planet formation are micrometer-sized dust grains that make up roughly 1% of the mass of a typical protoplanetary disk. In the Solar System, some 1040 of these grains evolved into a handful of rocky planets in the space of 10–100 million years – a remarkable transformation indeed.

Type
Chapter
Information
Protoplanetary Dust
Astrophysical and Cosmochemical Perspectives
, pp. 299 - 335
Publisher: Cambridge University Press
Print publication year: 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)
5
Cited by

Send book to Kindle

To send this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Send book to Dropbox

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox.

Available formats
×

Send book to Google Drive

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive.

Available formats
×