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[[Berkas:Artist's_impression_of_the_free-floating_planet_CFBDSIR_J214947.2-040308.9.ogv|jmpl|300x300px|Ilustrasi planet pengembara CFBDSIR J214947.2-040308.9. ]]
'''Planet pengembara''' (dalam bahasa Inggris disebut ''rogue planet'') adalah benda langit sebesar planet yang mengorbit pusat [[galaksi]] secara langsung. Objek semacam ini terlempar dari [[sistem keplanetan]] yang menjadi tempat terbentuknya planet ini, walaupun terdapat kemungkinan objek ini memang tidak pernah mengitari suatu bintang atau [[kataiKatai coklat|katai cokelat]].<ref name="shostak">Shostak, Seth (24 February 2005). ''Orphan Planets: It's a Hard Knock Life''. [http://www.space.com/ Space.com], 24 February 2005. Retrieved on 5 February 2009 from http://www.space.com/searchforlife/seti_orphan_planets_050224.html.</ref><ref name="lloyd">Lloyd, Robin (18 April 2001). ''Free-Floating Planets – British Team Restakes Dubious Claim''. Space.com, 18 April 2001. Retrieved on 5 February 2009 from http://www.space.com/scienceastronomy/astronomy/free_floaters_010403-1.html. {{Webarchive}}</ref><ref>Author unknown (18 April 2001). ''Orphan 'planet' findings challenged by new model''. [http://astrobiology.nasa.gov/ NASA Astrobiology], 18 April 2001. Retrieved on 5 February 2009 from {{Cite web|url=http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id%3D783|title=Archived copy|archive-url=https://web.archive.org/web/20090322091340/http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id=783|archive-date=22 March 2009|dead-url=yes|access-date=9 February 2009}}</ref> [[Bima Sakti|Galaksi Bima Sakti]] sendiri diperkirakan memiliki miliaran planet pengembara.<ref>[[Neil deGrasse Tyson]] in ''[[Cosmos: A Spacetime Odyssey]]'' as referred to by [http://phenomena.nationalgeographic.com/2014/03/13/a-guide-to-lonely-planets-in-the-galaxy/ National Geographic]</ref>
Beberapa planet pengembara mungkin terbentuk dengan cara yang sama seperti bintang, dan [[Persatuan Astronomi Internasional]] mengusulkan agar objek semacam itu disebut "katai sub-coklatcokelat".<ref>[http://www.dtm.ciw.edu/boss/definition.html Working Group on Extrasolar Planets – Definition of a "Planet"] Position Statement on the Definition of a "Planet" (IAU) {{Webarchive}}</ref> Contohnya adalah [[Cha 110913-773444]], yang mungkin terlempar dari sistem keplanetannya dan menjadi planet pengembara, atau terbentuk sendirian dan menjadi katai sub-cokelat.<ref name="CNN">[http://edition.cnn.com/2000/TECH/space/10/06/space.planets.reut/index.html Rogue planet find makes astronomers ponder theory]</ref>
Pada Desember 2013, diumumkan kemungkinan penemuan sebuah [[bulan luar surya]] yang mengelilingi sebuah planet pengembara.<ref>{{Cite journal|last=Bennett|first=D.P.|last2=Batista|first2=V.|displayauthors=etal|date=13 December 2013|title=A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic Bulge|journal=The Astrophysical Journal|volume=785|issue=2|pages=155|arxiv=1312.3951|bibcode=2014ApJ...785..155B|doi=10.1088/0004-637X/785/2/155}}</ref>
== Observasi ==
<span data-segmentid="31" class="cx-segment">Ahli astrofisika Takahiro Sumi dari Universitas Osaka di Jepang dan rekan-rekannya, yang membentuk Observasi Microlensing dalam Astrofisika dan kolaborasi Eksperimen Gravitasi Optik Lensa, menerbitkan studi mereka tentang [[ Microlensing|microlensing]] pada tahun 2011.</span> <span data-segmentid="33" class="cx-segment">Mereka mengamati 50 juta bintang di Bima Sakti menggunakan teleskop MOA-II 1,8 meter di [[ Observatorium Mount John|Observatorium Mount John]] Selandia Baru dan teleskop [[Universitas Warsawa]] 1,3 meter di [[ Observatorium Las Campanas|Observatorium Las Campanas]] Chile.</span> <span data-segmentid="37" class="cx-segment">Mereka menemukan 474 insiden microlensing, sepuluh di antaranya cukup singkat untuk menjadi planet seukuran Jupiter tanpa bintang terkait di sekitarnya.</span> <span data-segmentid="38" class="cx-segment">Para peneliti memperkirakan dari pengamatan mereka bahwa ada hampir dua planet pengembara bermassa Jupiter untuk setiap bintang di Bima Sakti. <ref>[http://news.sciencemag.org/sciencenow/2011/05/homeless-planets-may-be-common.html?ref=hp Homeless' Planets May Be Common in Our Galaxy] {{Webarchive}} by Jon Cartwright, Science Now, 18 May 2011, Accessed 20 May 2011</ref> <ref>[http://www.physorg.com/news/2011-05-class-planets.html Planets that have no stars: New class of planets discovered], Physorg.com, 18 May 2011. Accessed May 2011.</ref> <ref>{{Cite journal|last=T. Sumi|displayauthors=etal|date=2011|title=Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing|journal=Nature|volume=473|issue=7347|pages=349–352|arxiv=1105.3544v1|bibcode=2011Natur.473..349S|doi=10.1038/nature10092|pmid=21593867}}</ref></span> <span data-segmentid="39" class="cx-segment">Perkiraan lain menunjukkan jumlah yang jauh lebih besar, hingga 100.000 kali lebih banyak planet pengembara daripada bintang di Bima Sakti. <ref>{{Cite web|url=http://news.stanford.edu/news/2012/february/slac-nomad-planets-022312.html|title=Researchers say galaxy may swarm with 'nomad planets'|date=2012-02-23|publisher=[[Stanford University]]|access-date=29 February 2012}}</ref></span> <span data-segmentid="40" class="cx-segment">Sebuah studi tahun 2017 oleh Przemek Mróz dari Universitas Warsawa Observatory dan rekannya, dengan statistik enam kali lebih besar dari studi 2011, menunjukkan batas atas planet bermassa bebas Jupiter atau planet orbit lebar 0,25 planet per bintang urutan utama di Bima Sakti Cara. <ref>{{Cite journal|last=P. Mroz|displayauthors=etal|date=2017|title=No large population of unbound or wide-orbit Jupiter-mass planets|journal=Nature|volume=548|issue=7666|pages=183–186|arxiv=1707.07634|bibcode=2017Natur.548..183M|doi=10.1038/nature23276|pmid=28738410}}</ref></span>
<span data-segmentid="41" class="cx-segment">Kandidat planet pengembara terdekat termasuk [[ WISE 0855−0714|WISE 0855−0714]] pada jarak {{Val|7.27|0.13}} tahun cahaya. <ref name="Luhman2016">{{Cite journal|last=Luhman|first=Kevin L.|last2=Esplin|first2=Taran L.|date=September 2016|title=The Spectral Energy Distribution of the Coldest Known Brown Dwarf|journal=The Astronomical Journal|volume=152|issue=2|at=78|arxiv=1605.06655|bibcode=2016AJ....152...78L|doi=10.3847/0004-6256/152/3/78}}</ref></span>
== Retensi panas di ruang antar bintang ==
Planet luar surya menghasilkan sedikit panas dan tidak dipanaskan oleh sebuah bintang.<ref>{{Cite web|url=https://aeon.co/essays/could-we-make-our-home-on-a-rogue-planet-without-a-sun|title=Life in the dark|last=Sean Raymond|date=9 April 2005|publisher=Aeon|language=English|access-date=9 April 2016}}</ref> Pada tahun 1998, David J. Stevenson menduga bahwa beberapa objek seukuran planet di ruang antar bintang mungkin memiliki atmosfer tebal yang membuat permukaannya tidak beku.<ref name="Stevenson 1999">{{Cite journal|last=Stevenson|first=David J.|last2=Stevens|first2=C. F.|date=1999|title=Life-sustaining planets in interstellar space?|journal=Nature|volume=400|issue=6739|page=32|bibcode=1999Natur.400...32S|doi=10.1038/21811|pmid=10403246}}</ref>
== <span data-segmentid="70" class="cx-segment">Planet-planet Pengembara yang Dikenal</span> ==
<br />
<center>
{| class="wikitable sortable" style="text-align: center;"
|-
! Eksoplanet
! Massa ({{Jupiter mass|link=y}})
! Usia (Miliar Tahun)
! Jarak (tahun cahaya)
! Catatan
! Penemuan
|-
| [[OTS 44]] || ~11.5 || 0.5–3 || 554 ||[[Katai coklat]] bermassa rendah || 1998
|-
| [[S Ori 52]] || 2–8 || 1–5 || 1,150 || Usia dipertanyakan || 2000<ref>{{cite journal | title=Discovery of Young, Isolated Planetary Mass Objects in the σ Orionis Star Cluster | first=M. R. | last=Zapatero Osorio | date=6 October 2000 | journal=Science | volume=290 | issue=5489 | page=103 | doi=10.1126/science.290.5489.103 | bibcode=2000Sci...290..103Z}}</ref>
|-
| [[Cha 110913-773444]] || 5–15 || ~2 || 529 || Kandidat || 2004<ref>{{cite journal |title=Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk | first=Kevin L. | last=Luhman | date=10 December 2005 | journal=[[Astrophysical Journal Letters]] | volume=635 | issue=1 | pages=L93–L96 | doi=10.1086/498868 | bibcode=2005ApJ...635L..93L | arxiv=astro-ph/0511807}}</ref>
|-
| [[SIMP J013656.5+093347]] || 11-13 || ~200 || 20-22 || Kandidat || 2006<ref>{{cite journal|first1=Étienne|last1=Artigau|first2=René|last2=Doyon|first3=David|last3=Lafrenière|first4=Daniel|last4=Nadeau|title=Discovery of the Brightest T Dwarf in the Northern Hemisphere|url=http://stacks.iop.org/1538-4357/651/i=1/a=L57|journal=The Astrophysical Journal Letters|date= n.d. |issn=1538-4357|pages=L57|volume=651|issue=1|doi=10.1086/509146|first5=Jasmin|last5=Robert|first6=Loïc|last6=Albert|arxiv=astro-ph/0609419}}</ref><ref>{{cite journal|first1=Jonathan|last1=Gagné|first2=Jacqueline K.|last2=Faherty|first3=Adam J.|last3=Burgasser|first4=Étienne|last4=Artigau|title=SIMP J013656.5+093347 is Likely a Planetary-Mass Object in the Carina-Near Moving Group|journal=The Astrophysical Journal|date=15 May 2017|issn=2041-8213|pages=L1|volume=841|issue=1|doi=10.3847/2041-8213/aa70e2|first5=Sandie|last5=Bouchard|first6=Loïc|last6=Albert|first7=David|last7=Lafrenière|first8=René|last8=Doyon|first9=Daniella C.|last9=Bardalez-Gagliuffi|arxiv=1705.01625}}</ref>
|-
| [[UGPS J072227.51−054031.2]] || 5–40 || || 13 || Massa Tidak Pasti || 2010
|-
| [MPK2010b] 4450 || 2–3 || || 325 || Kandidat || 2010<ref>{{cite journal |title=A Young Planetary-Mass Object in the ρ Oph Cloud Core | first=Kenneth A. | last=Marsh | date=1 February 2010 | journal=[[Astrophysical Journal Letters]] | volume=709 | issue=2 | pages=L158–L162 | doi=10.1088/2041-8205/709/2/L158 | bibcode=2010ApJ...709L.158M | arxiv=0912.3774}}</ref>
|-
| [[CFBDSIR 2149−0403]] || 4–7 || 110–130 || 117–143 || Kandidat || 2012<ref>{{cite journal | title=CFBDSIR2149-0403: a 4-7 Jupiter-mass free-floating planet in the young moving group AB Doradus? | first=Philippe | last=Delorme | date=25 September 2012 | journal=[[Astronomy & Astrophysics]] | volume=548A | page=26 |doi=10.1051/0004-6361/201219984 | bibcode=2012A&A...548A..26D |arxiv=1210.0305}}</ref>
|-
| [[MOA-2011-BLG-262]] || ~4 || || || Kemungkinan [[katai merah]]|| 2013
|-
| [[PSO J318.5-22]] || 5.5–8 || 21–27 || 80 || Dikonfirmasi || 2013<ref>{{cite journal | title=The Extremely Red, Young L Dwarf PSO J318.5338-22.8603: A Free-floating Planetary-mass Analog to Directly Imaged Young Gas-giant Planets | first=Michael C. | last=Liu | date=10 November 2013 | journal=[[Astrophysical Journal Letters]] | volume=777 | issue=1 | pages=L20 | doi=10.1088/2041-8205/777/2/L20 | bibcode=2013ApJ...777L..20L|arxiv=1310.0457}}</ref>
|-
| [[2MASS J2208+2921]] || 11–13 || 21–27 || 115 || Kandidat || 2014<ref>{{cite journal | title=BANYAN. II. Very Low Mass and Substellar Candidate Members to Nearby, Young Kinematic Groups with Previously Known Signs of Youth | first=Jonathan | last=Gagné | date=10 March 2014 | journal=[[Astrophysical Journal]] | volume=783 | issue=2 | page=121 | doi=10.1088/0004-637X/783/2/121 | bibcode=2014ApJ...783..121G | arxiv=1312.5864}}</ref>
|-
| [[WISE J1741-4642]] || 4–21 || 23–130 || || Kandidat || 2014<ref>{{cite journal | title=Discovery of the Young L Dwarf WISE J174102.78-464225.5 | first=Adam C. | last=Schneider | date=9 January 2014 | journal=[[Astronomical Journal]] | volume=147 | issue=2 | page=34 | doi=10.1088/0004-6256/147/2/34 | bibcode=2014AJ....147...34S |arxiv=1311.5941}}</ref>
|-
| [[WISE 0855−0714]] || 3–10 || || 7.1 || Kemungkinan [[katai coklat]]|| 2014<ref>{{cite journal | title=Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun | first=Kevin L. | last=Luhman | date=10 May 2014 | journal=[[Astrophysical Journal Letters]] | volume=786 | issue=2 | page=L18 |doi=10.1088/2041-8205/786/2/L18 |bibcode=2014ApJ...786L..18L | arxiv=1404.6501}}</ref>
|-
| [[2MASS J12074836–3900043]] || 11–13 || 7–13 || 200 || Kandidat || 2014<ref>{{cite journal | title=The Coolest Isolated Brown Dwarf Candidate Member of TWA | first=Jonathan | last=Gagné | date=10 April 2014 | journal=[[Astrophysical Journal Letters]] | volume=785 | issue=1 | page=L14 | doi=10.1088/2041-8205/785/1/L14 | bibcode=2014ApJ...785L..14G | arxiv=1403.3120}}</ref>
|-
| [[SIMP J2154–1055]] || 9–11 || 30–50 || 63 || Usia dipertanyakan || 2014<ref>{{cite journal | title=SIMP J2154-1055: A New Low-gravity L4β Brown Dwarf Candidate Member of the Argus Association | first=Jonathan | last=Gagné | date=1 September 2014 | journal=[[Astrophysical Journal Letters]] | volume=792 | issue=1 | page=L17 | doi=10.1088/2041-8205/792/1/L17 | bibcode=2014ApJ...792L..17G | arxiv=1407.5344}}</ref>
|-
| [[SDSS J111010.01+011613.1]] || 10–12 || 110–130 || 63 || Konfirmasi || 2015<ref>{{cite journal | title=SDSS J111010.01+011613.1: A New Planetary-mass T Dwarf Member of the AB Doradus Moving Group | first=Jonathan | last=Gagné | date=20 July 2015 | journal=[[Astrophysical Journal Letters]] | volume=808 | issue=1 | page=L20 | doi=10.1088/2041-8205/808/1/L20 | bibcode=2015ApJ...808L..20G | arxiv=1506.04195}}</ref>
|-
| [[2MASS J1119–1137]] || 4–8 || 7–13 || 94 || Kandidat || 2016<ref>{{cite journal | title=The Nearest Isolated Member of the TW Hydrae Association is a Giant Planet Analog | first=Kendra | last=Kellogg | date=11 April 2016 | journal=[[Astrophysical Journal Letters]] | volume=821 | issue=1 | page=L15 | doi=10.3847/2041-8205/821/1/L15 | bibcode=2016ApJ...821L..15K | arxiv=1603.08529}}</ref>
|-
| [[WISEA 1147]] || 5–13 || 7–13 || 94 || Kandidat || 2016<ref>{{cite journal | title=WISEA J114724.10-204021.3: A Free-floating Planetary Mass Member of the TW Hya Association | first=Adam C. | last=Schneider | date=21 April 2016 | journal=[[Astrophysical Journal Letters]] | volume=822 | issue=1 | page=L1 | doi=10.3847/2041-8205/822/1/L1 | bibcode=2016ApJ...822L...1S | arxiv=1603.07985}}</ref>
|-
| [[OGLE-2012-BLG-1323]] || 0.007245–0.07245 || || || Kandidat || 2017<ref>{{cite web | url=https://motherboard.vice.com/en_us/article/ev3dkj/rare-sighting-of-two-rogue-planets-that-do-not-orbit-stars | title=Rare Sighting of Two Rogue Planets That Do Not Orbit Stars | publisher=Motherboard | language=English | author=Becky Ferreira | date=9 Nov 2018 | accessdate=10 February 2019}}</ref><ref>{{cite web | url=http://blogs.discovermagazine.com/d-brief/2018/11/16/rogue-planets-discovered/#.XEeAI2l7mUk | title=These Two New 'Rogue Planets' Wander the Cosmos Without Stars | publisher=Discover Magazine | language=English | author=Jake Parks | date=16 November 2018 | accessdate=10 February 2019}}</ref><ref>{{cite web | url=http://www.astronomy.com/news/2018/11/rogue-one-and-two | title=Two free-range planets found roaming the Milky Way in solitude | publisher=Astronomy Magazine | language=English | author=Jake Parks | date=15 November 2018 | accessdate=10 February 2019}}</ref>
|-
| [[OGLE-2017-BLG-0560]] || 1.9–20 || || || Kandidat || 2017<ref>{{cite web | url=https://motherboard.vice.com/en_us/article/ev3dkj/rare-sighting-of-two-rogue-planets-that-do-not-orbit-stars | title=Rare Sighting of Two Rogue Planets That Do Not Orbit Stars | publisher=Motherboard | language=English | author=Becky Ferreira | date=9 Nov 2018 | accessdate=10 February 2019}}</ref><ref>{{cite web | url=http://blogs.discovermagazine.com/d-brief/2018/11/16/rogue-planets-discovered/#.XEeAI2l7mUk | title=These Two New 'Rogue Planets' Wander the Cosmos Without Stars | publisher=Discover Magazine | language=English | author=Jake Parks | date=16 November 2018 | accessdate=10 February 2019}}</ref><ref>{{cite web | url=http://www.astronomy.com/news/2018/11/rogue-one-and-two | title=Two free-range planets found roaming the Milky Way in solitude | publisher=Astronomy Magazine | language=English | author=Jake Parks | date=15 November 2018 | accessdate=10 February 2019}}</ref>
|}
</center>
== Referensi ==
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