Tazama chanzo cha Sayari ya Tisa

[[Picha:Planet nine artistic plain.png|300px|thumb|Wazo la mchoraji kuhusu Sayari Tisa; jua linaonekana kwa mbali sana, na mstari wa duaradufu ni njia ya sayari ya nane Neptun]]
[[Picha:Sayari za Jua - mlingano ukubwa.png|300px|thumb|Sayari Tisa imekadiriwa kufanana na sayari za rangi buluu kwenye picha hii ya mlingano wa ukubwa wa sayari za jua letu.]]
'''Sayari ya Tisa''' (pia '''Sayari Tisa''', kwa [[Kiingereza]] ''[[:en:Planet Nine|Planet Nine]]'') ni [[jina]] la [[muda]] kwa [[sayari]] isiyojulikana bado lakini inayoaminiwa kuwepo kwenye sehemu za nje kabisa za [[mfumo wa jua letu]].

Hadi mwaka 2006 [[Pluto]] ilihesabiwa kama sayari ya tisa; lakini mwaka ule ufafanuzi mpya ulisababisha kuhesabiwa kwake kama "[[sayari kibete]]". Kwa hiyo sasa sayari inayoaminiwa kuwepo nje ya obiti ya Pluto huitwa "ya tisa".

Hadi sasa Sayari Tisa haijaonekana moja kwa moja, hivyo ni sayari ya [[kinadharia tete]]. 

==Sababu za kutunga nadharia tete ya Sayari Tisa==
Kuwepo kwa sayari hii imependekezwa na [[wataalamu]] wa [[astronomia]] baada ya kutazama miendo ya ajabu katika [[kundi]] la [[gimba la angani|magimba]] yaliyopo kwenye mpaka wa nje wa [[ukanda wa Kuiper]]; magimba hayo ni [[asteroidi]] na angalau [[sayari kibete]] [[moja]]. Hadi sasa magimba [[sita]] yametambuliwa ambayo [[obiti]] zake za kuzunguka [[jua]] hazifuati njia inayolingana na magimba mengine. 

Walipotafuta kwa nini obiti hizo si za kawaida, [[wataalamu]] walianza kuwaza ya kwamba kuna [[kitu]] chenye [[masi]] kubwa kinachoathiri magimba hayo na kubadilisha njia zake. Awali mawazo yalitofautiana kama ni kitu kimoja au labda vitu viwili huko nje.

==Historia ya uchunguzi na nadharia==
* '''Mwaka 2004''': kutambuliwa kwa [[asteroidi]] au [[sayari kibete]] inayoitwa [[90377 Sedna|Sedna]] inayotembea nje ya Ukanda wa Kuiper kwenye [[umbali]] wa [[vizio astronomia]] 76 - 936 kutoka [[jua]]. [[Umbo]] la obiti yake lilistaajabisha watazamaji. Walitafuta sababu za Sedna kuwa na njia hii nje ya Ukanda wa Kuiper; sababu zilizotajwa zilikuwa [[nyota]] nyingine iliyowahi kupita karibu na jua letu au sayari nyingine huko nje isiyojulikana bado. <ref name=spaceBrown>{{cite web |url=http://www.space.com/12711-pluto-killer-mike-brown-dwarf-planets-interview.html |title=A Conversation With Pluto's Killer: Q & A With Astronomer Mike Brown|author= Mike Wall|website=[[Space.com]] |date= 24 August 2011 | access-date = 7 February 2016}}</ref><ref name=iopsciencesedna>{{cite journal |doi=10.1086/422095 |url=http://iopscience.iop.org/article/10.1086/422095/pdf |title=Discovery of a Candidate Inner Oort Cloud Planetoid |journal=[[The Astrophysical Journal]] |volume=617 |issue=1 |pages=645–649 |arxiv = astro-ph/0404456 |bibcode = 2004ApJ...617..645B }}</ref><ref name=brownsedna>{{cite web |url=http://www.mikebrownsplanets.com/2010/10/theres-something-out-there-part-2.html |first=Michael E. |last=Brown |author-link=Michael E. Brown |website=Mike Brown's Planets |date=28 October 2010 |title=There's something out there – part 2}}</ref>
* '''Mwaka 2008''': Hadi mwaka huo obiti nyingine za magimba ya ng'ambo ya [[Neptun]] zilitambuliwa zilizotembea nje ya obiti za kawaida. [[Mwanaastronomia]] wa [[Japani]] [[Tadashi Mukai]] na wenzake waliwaza kuwepo kwa sayari yenye ukubwa wa [[Dunia]] au [[Mirihi]] kwenye umbali wa vizio astronomia 100 hadi 200 .<ref name=LykawaMukai>
{{cite journal
|first= Lykawka
|last= Patryk S.
|first2= Mukai
|last2 = Tadashi
|title= An Outer Planet Beyond Pluto and the Origin of the Trans-Neptunian Belt Architecture
|url= https://archive.org/details/sim_astronomical-journal_2008-04_135_4/page/1161
|journal=[[The Astronomical Journal]]
|date=April 2008
|volume=135
|issue=4
|pages=1161–1200
|doi=10.1088/0004-6256/135/4/1161
|bibcode = 2008AJ....135.1161L|arxiv = 0712.2198 }}
</ref><ref name=natgeoPlutoid>{{cite web |url=http://news.nationalgeographic.com/news/2008/03/080317-new-planet.html |title=Earth-Size Planet to Be Found in Outer Solar System? }}</ref><ref name=spaceplanetX>{{cite web |url=http://www.space.com/5526-large-planet-lurk-pluto.html |title=Large 'Planet X' May Lurk Beyond Pluto }}</ref><ref name=canwestPlanetX>{{cite web |url=http://www.canada.com/topics/technology/science/story.html?id=ad663127-e12a-4050-a59c-12c3253f99b6 |title=Japanese scientists eye mysterious 'Planet X' |accessdate=2016-05-06 |archivedate=2016-04-02 |archiveurl=https://web.archive.org/web/20160402053540/http://www.canada.com/topics/technology/science/story.html?id=ad663127-e12a-4050-a59c-12c3253f99b6 }}</ref>
* '''Mwaka 2012''': [[Rodney Gomez]] wa [[Brazil]] alichungulia obiti za magimba nje ya Neptun akaona kundi lenye obiti zisizo za kawaida; akaunda kielelezo cha [[hesabu]] iliyoonyesha ya kwamba kuwepo kwa sayari yenye masi kati ya Mirihi na Neptun ikitembea mbali sana na jua kunaeleza umbo la obiti zisizo za kawaida.<ref name=llmysteries>{{cite web |url=http://www.livescience.com/20583-planet-edge-solar-system.html |title=Planet X? New Evidence of an Unseen Planet at Solar System's Edge|date=25 May 2012|author=Natalie Wolchover |website=[[LiveScience]] | access-date = 7 February 2016 |quote=More work is needed to determine whether Sedna and the other scattered disc objects were sent on their circuitous trips round the sun by a star that passed by long ago, or by an unseen planet that exists in the solar system right now. Finding and observing the orbits of other distant objects similar to Sedna will add more data points to astronomers' computer models.}}</ref><ref name="Gomes_2015">{{cite journal |last1=Gomes |first1=Rodney |title=The observation of large semi-major axis Centaurs: Testing for the signature of a planetary-mass solar companion |journal=Icarus |date=2015 |volume=258 |pages=37–49 |bibcode=2015Icar..258...37G |doi=10.1016/j.icarus.2015.06.020 }}</ref> Wataalamu wengine walisema ya kwamba alishindwa kuonyesha uthibitisho wa kuwepo kwa sayari huko nje.<ref name=nosmokingGun>{{cite web |url=http://news.nationalgeographic.com/news/2012/05/120511-new-planet-solar-system-kuiper-belt-space-science/ |title=New Planet Found in Our Solar System? }}</ref>
* '''Mwaka 2014''': Magimba mengine yanayofanana na Sedna na obiti yake yalitambuliwa. Ugunduzi huo uliongeza uwezekano wa kuwepo kwa sayari kubwa katika umbali ya nje.<ref name=guardianSuperEarth>{{cite news |url=http://www.theguardian.com/science/2014/mar/26/dwarf-planet-super-earth-solar-system-2012-vp113 |title=Dwarf planet discovery hints at a hidden Super Earth in solar system| newspaper= Guardian News |date= 26 March 2014 |author=Ian Sample }}</ref>
* '''2014 tena''': Uchunguzi wa obiti 12 za mbali nje ya Neptun, na hasa kulinganisha kwa [[afeli]] na [[periheli]] zake, uliofanywa na Trujillo na Sheppard ulileta tokeo ya kwamba usumbufu wa obiti zao hauwezi kuelezwa na [[nguvu]] za [[graviti]] zilizopo ndani ya mfumo wa jua jinsi unavyoonekana hadi sasa, sharti kuwe na kitu nje. <ref name=sciencenews>{{cite web|url=https://www.sciencenews.org/article/distant-planet-may-lurk-far-beyond-neptune|title=A distant planet may lurk far beyond Neptune|author=Christopher Crocket|date= 14 November 2014|work=[[Science News]] | archive-url = https://web.archive.org/web/20150415165100/https://www.sciencenews.org/article/distant-planet-may-lurk-far-beyond-neptune/ | archive-date =15 April 2015| access-date = 7 February 2015 | dead-url = no}}</ref><ref name=stealingsedna>{{cite web|url=http://www.universetoday.com/121637/stealing-sedna/ |title=Stealing Sedna|author= David Dickinson|date=6 August 2015|work=[[Universe Today]] | access-date =7 February 2016}}</ref>

==Kielelezo cha Sayari ya Tisa==
Kufuatana na makadirio ya [[Konstantin Batygin]] na [[Michael E.&nbsp;Brown]] wa [[California Institute of Technology]] (Caltech) ya mwaka [[2016]], uwezekano wa kuwepo kwa Sayari ya Tisa ni mkubwa. Waliingiza [[data]] zote za obiti katika vielelezo vya [[kompyuta]], wakafikia suluhisho la kwamba, kuwepo kwa sayari kubwa inayozunguka jua katika umbali mkubwa nje ya ukanda wa Kuiper kunaweza kueleza mambo yasiyo ya kawaida ya obiti zilizochunguliwa. <ref Name="Achenbach/Feltman">[https://www.washingtonpost.com/news/speaking-of-science/wp/2016/01/20/new-evidence-suggests-a-ninth-planet-lurking-at-the-edge-of-the-solar-system  New evidence suggests a ninth planet lurking at the edge of the solar system], [[The Washington Post]] 2016-01-20, iliangaliwa 2016-01-21</ref>

Katika [[hesabu]] yao Sayari ya Tisa ingekuwa sayari jito ya [[gesi]] yenye masi takriban mara [[Kumi (namba)|kumi]] kuliko [[dunia]]. Brown anawaza ya kwamba sayari itagunduliwa katika miaka mitano ijayo. <ref>[http://www.theguardian.com/science/2016/jan/20/ninth-planet-solar-system-edge-discovery-pluto Evidence suggests huge ninth planet exists past Pluto at solar system’s edge], TheGuardian.com 20&nbsp;Januari 2016, iliangaliwa 20 &nbsp;Januari 2016]</ref> Kama ina masi hii na kama muundo wake unafanana na [[Uranus]] na [[Neptun]], ni lazima sayari hii iwe na kipenyo mara 3.7 za dunia (km 46,600) na [[halijoto]] usoni ya K 47 (−226°C).
<ref>{{cite journal
 | author = Esther F. Linder, Christoph Mordasini
 | year = 2016
 | month = 04
 | title = Evolution and magnitudes of candidate Planet Nine
 | journal = Astronomy & Astrophysics
 | volume = 
 | issue = 
 | pages = 
 | bibcode =
 | doi = 10.1051/0004-6361/201628350
 | pmid =
 | arxiv = 1602.07465
 | id = 
 | url = http://arxiv.org/pdf/1602.07465.pdf
 | format = PDF
 | accessdate = 2016-04-08
 }}</ref>

Katika kielelezo obiti ya Sayari ya Tisa ingekuwa kabisa nje ya obiti ya Neptun. 

==Nadharia tete mbadala==
Uwepo wa Sayari ya Tisa haujakubaliwa na wanaastronomia wote. Kuna [[nadharia]] mbadala. Zote zinakubali kuna kitu nje ambacho kutokana na [[graviti]] yake kinasumbua obiti za magimba zilizopimwa.

===Magimba mengi yasiyotambuliwa bado===
[[Ann-Marie Madigan]] na [[Michael McCourt]] wameangalia uwezekano wa kuwepo kwa ukanda wenye masi kubwa kushinda [[ukanda wa Kuiper]] huko nje ambao haujatambuliwa bado. <ref name=planet9ornot>{{cite web |url=https://www.yahoo.com/tech/this-week-in-space-weird-pluto-and-no-plan-for-183233179.html |title=Why Planet Nine might not exist }}</ref><ref name=spaceplanet9>{{cite web |url=http://www.space.com/31817-planet-nine-existence-question.html |title='Planet Nine'? Cosmic Objects' Strange Orbits May Have a Different Explanation |quote="We need more mass in the outer solar system," she (Madigan) said. "So it can either come from having more minor planets, and their self-gravity will do this to themselves naturally, or it could be in the form of one single massive planet — a Planet Nine. So it's a really exciting time, and we're going to discover one or the other."}}</ref>

=== Masi ya ziada isiyotambuliwa bado pamoja na Sayari Tisa ===
[[Matthew J. Holman]] na [[Matthew J. Payne]] kwenye Harvard–Smithsonian Center for Astrophysics walichungulia obiti ya [[Pluto]] wakaona mikengeuko mikubwa kushinda [[utabiri]] wa Batygin na Brown. Waliona njia [[tatu]] za kueleza tofauti hizo
* inawezekana data zinazohusu obiti ya Pluto zina makosa makubwa
*inawezekana bado kuna masi isiyotambuliwa ndani ya mfumo wa jua letu, kama vile sayari ndogo, pamoja na Sayari ya Tisa inayowezekana nje.
* inawezekana kuna sayari iliyo ama kubwa zaidi au iko karibu zaidi na jua kuliko Sayari ya Tisa iliyotabiriwa na Batygin na Brown.<ref>{{cite arXiv|title=Observational Constraints on Planet Nine: Astrometry of Pluto and Other Trans-Neptunian Objects|arxiv=1603.09008|first1=Matthew J.|last1=Holman|first2=Matthew J.|last2=Payne|class=astro-ph.EP|volume= |issue= |pages=|date=30 Mar 2016}}</ref>

==Uhakiki==
Uhakiki wa nadharia unahitaji kutambua Sayari ya Tisa au magimba mengine kwa [[vipimo]]. Hii haitakuwa rahisi. Sayari zinaonekana kwa sababu zinaakisia [[nuru]] ya jua. Katika umbali mkubwa vile ni nuru ndogo sana inayofika kutoka jua na kiasi kidogo zaidi kinachoweza kuakisiwa tena. Kwa hiyo ingeonekana kama [[nukta]] hafifu sana kwa [[darubini]] za astronomia. Njia ya pekee inategemea [[tabia]] ya sayari inayobadilisha mahali pake [[Anga|angani]] hata kama ni polepole, tofauti na nyota zinazokaa mahali pamoja. Hapa watazamaji wanapiga [[picha]] nyingi za maeneo wanayochungulia wanapoona mamilioni ya nyota. Sasa wanalinganisha kwa [[kompyuta]] kama kuna nukta za nuru zinazobadili mahali. Katika chaguo la sehemu wanapochungulia wanategemea utabiri zinazowezekana kutegemeana na vielelezo. 

Uwezekano utategemea pia mahali pa Sayari ya Tisa kenye obiti yake - kama iko karibu na [[periheli]] yake itakuwa rahisi zaidi; kama iko karibu na [[afeli]] yake itakuwa vigumu zaidi.

{{mbegu-sayansi}}

==Marejeo==
<references/>

[[Jamii:Sayari]]
[[Jamii:Mfumo wa jua]]