Editing Protoplanetary disk (section)

==Planetary system==
[[File:Soot-line1.jpg|thumb|upright=2|An artist's illustration giving a simple overview of the main regions of a protoplanetary disk, delineated by the soot and frost line, which for example has been observed around the star [[V883 Orionis]].<ref>{{cite web|title=Stellar Outburst Brings Water Snow Line Into View|url=http://www.eso.org/public/news/eso1626/|access-date=15 July 2016}}</ref>]]

The [[solar nebula|nebular hypothesis]] of solar system formation describes how protoplanetary disks are thought to evolve into planetary systems. Electrostatic and gravitational interactions may cause the dust and ice grains in the disk to accrete into [[planetesimal]]s. This process competes against the [[stellar wind]], which drives the gas out of the system, and gravity ([[accretion disk|accretion]]) and internal stresses ([[viscosity]]), which pulls material into the central T Tauri star. Planetesimals constitute the building blocks of both terrestrial and giant planets.<ref name=lhdb2009>{{cite journal|last=Lissauer|first=J. J.|author2=Hubickyj, O. |author3=D'Angelo, G. |author4=Bodenheimer, P. |title=Models of Jupiter's growth incorporating thermal and hydrodynamic constraints| journal=Icarus|year=2009|volume=199|issue=2| pages=338–350|arxiv=0810.5186|doi=10.1016/j.icarus.2008.10.004|bibcode=2009Icar..199..338L |s2cid=18964068}}</ref><ref name=dangelo2014>{{cite journal|last=D'Angelo|first=G.|author2=Weidenschilling, S. J. |author3=Lissauer, J. J. |author4=Bodenheimer, P. |title=Growth of Jupiter: Enhancement of core accretion by a voluminous low-mass envelope|journal=Icarus|date=2014|volume=241|pages=298–312|arxiv=1405.7305|doi=10.1016/j.icarus.2014.06.029|bibcode=2014Icar..241..298D|s2cid=118572605}}</ref>

[[File:Disk comet nebula.jpg|thumb|upright=2|A model of a protoplanetary disk]]

Some of the moons of [[Jupiter]], [[Saturn]], and [[Uranus]] are believed to have formed from smaller, circumplanetary analogs of the protoplanetary disks.<ref name="arxiv0812">{{cite book |author1=Canup, Robin M. |author1-link=Robin Canup |author2=Ward, William R. |title=Origin of Europa and the Galilean Satellites |publisher=[[University of Arizona Press]] |date=2008-12-30 |arxiv=0812.4995|bibcode = 2009euro.book...59C |page=59|isbn=978-0-8165-2844-8}}</ref><ref name=dangelo_podolak_2015>{{cite journal|last=D'Angelo|first=G.|author2= Podolak, M.|title=Capture and Evolution of Planetesimals in Circumjovian Disks|journal=The Astrophysical Journal|date=2015|volume=806|issue=1|pages=29pp|doi=10.1088/0004-637X/806/2/203|arxiv = 1504.04364 |bibcode = 2015ApJ...806..203D |s2cid=119216797}}</ref>  The formation of planets and moons in geometrically thin, gas- and dust-rich disks is the reason why the [[planets]] are arranged in an [[ecliptic plane]]. Tens of millions of years after the formation of the Solar System, the inner few AU of the Solar System likely contained dozens of moon- to Mars-sized bodies that were accreting and consolidating into the terrestrial planets that we now see. The Earth's moon likely formed after a Mars-sized protoplanet obliquely [[Giant impact hypothesis|impacted]] the proto-Earth ~30 million years after the formation of the Solar System.