DUNIYAR DA KE ZAMA TURURI

Wasu duniyoyin dutse suna kewaye tauraronsu kusa sosai har samansu yana kaiwa yanayin zafin da dutse ke zama tururi. Idan duniyar ƙarama ce isasshe, wannan tururin ma’adinai yana tserewa, yana bazuwa kuma wani ɓangarensa yana daskarewa ya zama ƙura. Idan aka duba daga Duniya, irin wannan duniya ba ta jefa inuwa zagaye mai tsabta lokacin da take wucewa a gaban tauraronta: hasken tauraron yana dushewa ba bisa tsari ba, ba daidai ba, daga wucewa ɗaya zuwa wata, saboda wani gajimaren ƙura da ke biye a baya ne ke yin yawancin ɓoyewar. Waɗannan su ne duniyoyin dutse da ke wargajewa (disintegrating rocky planets). ’Yan kaɗan ne kawai aka sani.

Har zuwa yanzu, abin da masana ilimin taurari suka gani yana tserewa daga gare su galibi ƙura ce. Duk da haka lissafi yana hasashen cewa tururin yana ƙunshe da ƙwayoyin zarra da ƙwayoyin halitta (molecules) — sodium, silicon monoxide, magnesium, ƙarfe, kuma fiye da duka oxygen, babban sinadarin dutse. Neman sodium ko calcium a irin waɗannan tsarin galibi ya ƙare da iyakoki na sama kawai.

Duniyar da ke kewayawa cikin awa 30

BD+05 4868 Ab tana kewaye wani tauraro mai haske, ƙarami irin na K (K-type dwarf), cikin kwana 1.27. Wucewarta tana dushe tauraron da kashi 0.8 zuwa 2, da wata gajeriyar jelar ƙura a gaba da wata mafi tsayi sosai a baya. A cewar binciken baya da takardar ta gina a kai, tana zubar da ƙura kusan gram 2 × 10¹² a kowace daƙiƙa, kuma samanta da ke fuskantar tauraron yana kusan kelvin 1,820.

Neman oxygen da ƙaramin madubin hangen nesa

Kody Walker da James Wallace, na Jami’ar Indiana State, sun nufi wata takamammiyar alamar yatsa ta oxygen: layukan shanye haske uku kusa da ångström 7,774, a ƙarshen ja na bakan haske da ake gani. Waɗannan layuka suna farawa ne daga wani yanayin ɗaukaka (excited state) na ƙwayar zarrar oxygen wanda zafi kaɗai ba zai iya cikawa a kelvin 1,820 ba — damar ta kusan 5 cikin 10²⁶. Idan suka bayyana, dole wani abu daban ne ke ɗaukaka ƙwayoyin zarran: hasken ultraviolet daga tauraron yana fizge electrons, kuma ƙwayoyin zarra da suka sake kama ɗaya suna saukowa mataki-mataki ta wannan yanayin ɗaukaka.

Na’urarsu mai sauƙi ce: madubin hangen nesa mai santimita 43 a Leif Everson Observatory a Sturgeon Bay, Wisconsin, da na’urar raba haske (spectrograph) mai ƙaramin daidaito. Tana dusashe layukan oxygen uku, masu nisan ångström 3.45 kawai da juna, zuwa wani tabo ɗaya na ångström 13. A cikin dare takwas tsakanin Mayu da Yuli 2025, sun rubuta bakan haske 24 a lokacin wucewar jelar ƙura da 73 a wajenta. An jera bakan hasken bisa lokacin kewayawa, ba bisa kamanninsu ba, kuma an lissafa gyaran sararin iskar Duniya ba tare da duba yankin oxygen ba. Ma’aunin haske (photometry) daga wasu madubin hangen nesa biyu ya tabbatar da cewa duniyar tana zubar da ƙura a lokacin.

Raguwar kashi 9

A lokacin wucewa, bakan hasken yana nuna ƙarin shanye haske kusa da ångström 7,774 wanda babu shi a wajen wucewa: zurfinsa ya kai kusan kashi 9, faɗinsa daidai da dusashewar na’urar. Marubutan sun jaddada cewa rashin tabbacin da suka bayar zango ne da ke rufe zaɓuɓɓukan nazari masu ma’ana, ba wani muhimmanci na ƙididdiga a hukumance ba (formal statistical significance).

Matsakaicin bakan haske a lokacin wucewa (a) da a wajensu (b); wuraren da aka inuwantar suna nuna rashin tabbaci. — Hoto na 3, Walker & Wallace (2026), arXiv:2610.04986.

Iskar da ta wuce ƙurar

Wani samfuri mai sauƙi na iskar oxygen da tauraron ke haskakawa zai iya sake samar da raguwar: ƙarfi ɗaya, zurfi ɗaya, faɗi ɗaya da zarar na’urar ta dusashe shi. Ƙwayar zarrar oxygen ɗaya kawai cikin miliyan goma ake buƙata ta kasance a yanayin ɗaukaka. Amma dole iskar ta faɗaɗa nesa da siraran layin ƙura, ta rufe kusan kashi ɗaya bisa uku na fuskar tauraron; idan an taƙaita ta a layin ƙura, za ta buƙaci adadi marasa ma’ana. A cikin mafita ta wakilci, duniyar za ta riƙa rasa iska kusan ninki biyar fiye da ƙura — lamba da marubutan suka ce ta dogara da samfurin, ba ma’auni ba ce.

Tauraron zai iya zama mai yaudara

Marubutan sun riƙe lakabin “abin da ake zato” (candidate). Tauraron kansa yana da waɗannan layukan oxygen, kuma siffarsu tana bambanta a faɗin fuskarsa. Lokacin da jelar ƙura ta ɓoye wani ɓangare na wannan fuska, kwatanta bakan haske na lokacin wucewa da na wajenta zai iya nuna raguwa ko da babu oxygen na duniyar. A wannan daidaito, ba za a iya bambanta su biyun ba. Gurɓacewa daga sararin iskar Duniya ba ta yi musu kama da mai yiwuwa sosai ba, amma ba a cire ta gaba ɗaya ba.

Bakan haske mafi kaifi tuni suna nan

Gwajin yana kusa: bakan haske bakwai masu babban daidaito na tauraron, waɗanda wata ƙungiya ta baya ta ɗauka da madubin hangen nesa na WIYN mai mita 3.5, suna raba layukan uku sarai. Siginar duniya ya kamata ta zo ta tafi tare da kewayawar duniyar; layukan tauraron kuma kada su yi haka. Idan aka tabbatar, zai zama alaƙa ta farko tsakanin ƙura da iskar ƙwayoyin zarra ta wata duniya da ke tafasa tana ƙarewa.