Editing Planetary system (section)

==Origin and evolution==
{{See also|Nebular hypothesis|Planetary migration|Formation and evolution of the Solar System}}
[[File:Opo0113i.jpg|thumb|upright=1.5|Illustration of the dynamics of a [[proplyd]]]]
Planetary systems come from [[protoplanetary disk]]s that form around stars as part of the process of [[star formation]].

During formation of a system, much material is gravitationally-scattered into distant orbits, and some planets are ejected completely from the system, becoming [[rogue planet]]s.

===Evolved systems===

====High-mass stars====
Planets orbiting [[pulsar]]s have been discovered. Pulsars are the remnants of the [[supernova]] explosions of high-mass stars, but a planetary system that existed before the supernova would likely be mostly destroyed. Planets would either evaporate, be pushed off of their orbits by the masses of gas from the exploding star, or the sudden loss of most of the mass of the central star would see them escape the gravitational hold of the star, or in some cases the supernova would [[pulsar kick|kick]] the pulsar itself out of the system at high velocity so any planets that had survived the explosion would be left behind as free-floating objects. Planets found around pulsars may have formed as a result of pre-existing stellar companions that were almost entirely evaporated by the supernova blast, leaving behind planet-sized bodies. Alternatively, planets may form in an [[accretion disk]] of fallback matter surrounding a pulsar.<ref>{{cite journal|bibcode=1993ASPC...36..149P|title=Planet formation scenarios|last1=Podsiadlowski|first1=Philipp|volume=36|date=1993|pages=149|journal=In: Planets Around Pulsars; Proceedings of the Conference}}</ref> Fallback disks of matter that failed to escape orbit during a supernova may also form planets around [[black hole]]s.<ref name="fallback">{{cite journal |last1=Perna |first1=Rosalba |title=The Fate of Fallback Matter Around Newly Born Compact Objects |date=2013-12-17 |last2=Duffell |first2=Paul |last3=Cantiello |first3=Matteo |last4=MacFadyen |first4=Andrew |journal=The Astrophysical Journal |volume=781 |issue=2 |page=119 |doi=10.1088/0004-637X/781/2/119 |arxiv=1312.4981 |author-link1=Rosalba Perna}}</ref>

====Lower-mass stars====
[[File:Protoplanetary discs observed with SPHERE.jpg|thumb|Protoplanetary discs observed with the [[Very Large Telescope]].<ref>{{cite web|title=Sculpting Solar Systems - ESO's SPHERE instrument reveals protoplanetary discs being shaped by newborn planets|url=https://www.eso.org/public/news/eso1640/|website=www.eso.org|access-date=December 7, 2016}}</ref>]]
As stars evolve and turn into [[red giant]]s, [[asymptotic giant branch]] stars, and [[planetary nebula]]e they engulf the inner planets, evaporating or partially evaporating them depending on how massive they are.<ref name="NYT-20230503">{{cite news |last=Ferreira |first=Becky |title=It's the End of a World as We Know It - Astronomers spotted a dying star swallowing a large planet, a discovery that fills in a "missing link" in understanding the fates of Earth and many other planets. |url=https://www.nytimes.com/2023/05/03/science/star-eating-planet.html |date=3 May 2023 |work=[[The New York Times]] |url-status=live |archiveurl=https://archive.today/20230503155540/https://www.nytimes.com/2023/05/03/science/star-eating-planet.html |archivedate=3 May 2023 |accessdate=3 May 2023 }}</ref><ref name="NYT-20220819">{{cite news |last=Ferreira |first=Becky |title=The Juicy Secrets of Stars That Eat Their Planets - As scientists study thousands of planets around the galaxy, they are learning more about worlds that get swallowed up by their stars. |url=https://www.nytimes.com/2022/08/19/science/stars-planets-engulfment.html |date=19 August 2022 |work=[[The New York Times]] |accessdate=19 August 2022 }}</ref> As the star loses mass, planets that are not engulfed move further out from the star.

If an evolved star is in a binary or multiple system, then the mass it loses can transfer to another star, forming new protoplanetary disks and second- and third-generation planets which may differ in composition from the original planets, which may also be affected by the mass transfer.
<!--External links in an article like this are inappropriate. If they can be used as references, then please add them as as inline citations to whatever claim they support. Otherwise, please remove them and this hidden comment-->
<!--*[https://arxiv.org/abs/1012.0572 Planets in evolved binary systems], Hagai B. Perets, January 13, 2011
*[https://arxiv.org/abs/astro-ph/0702724 Can Planets survive Stellar Evolution?], Eva Villaver, Mario Livio, Feb 2007
*[https://arxiv.org/abs/0910.2396 The Orbital Evolution of Gas Giant Planets around Giant Stars], Eva Villaver, Mario Livio, October 13, 2009
*[https://arxiv.org/abs/1210.0879 On the survival of brown dwarfs and planets engulfed by their giant host star], Jean-Claude Passy, Mordecai-Mark Mac Low, Orsola De Marco, October 2, 2012
*[https://arxiv.org/abs/1210.0328 Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs], Alexander James Mustill, Eva Villaver, December 5, 2012
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