ƘARAR WATA SUPERNOVA TA JUYA BAYA, KAMAR YADDA AKA FAƊA

Supernovae masu haske fiye da kima (superluminous supernovae) suna haskakawa fiye da na yau da kullum aƙalla sau goma. Abin da ke ba su ƙarfi har yanzu tambaya ce a buɗe. Wani babban ra’ayi shi ne sabon magnetar da aka haifa: tauraron neutron (neutron star) mai saurin juyawa da ke zuba makamashin juyawarsa a cikin tarkacen fashewar. Wannan inji ya kamata ya sa haske ya dushe a hankali ba tare da tsaiko ba bayan kololuwarsa. Duk da haka 50 zuwa 70% na waɗannan supernovae suna nuna tuddai a cikin layukan haskensu (light curves). Bayanai biyu suna gogayya: inji mai kyalkyali, ko tarkacen da ke faɗawa kan bawo-bawon iskar gas da tauraron ya zubar a baya.

Supernova ta farko da ta yi ƙarar tsuntsu

An gano SN 2024afav a Disamba 2024, kimanin megaparsecs 327 daga nan. A wata takarda ta baya, Joseph Farah, Logan Prust da abokan aikinsu sun nuna cewa tuddanta suna ƙara kusantar juna: tazarar lokaci tsakaninsu ta ragu daga kimanin kwanaki 39 zuwa kwanaki 17, tsakanin rana ta 99 da rana ta 166 bayan fashewar. Kamar kukan tsuntsu da sautinsa ke hawa, ta yi ƙara mai hawa (chirp) — supernova ta farko da aka sani ta yi haka.

Bayaninsu: wani faifai a karkace na iskar gas da ke komawa yana faɗowa kan magnetar, yana raurawa kamar abin wasan yara mai juyawa a kan tsininsa (spinning top), abin da ke sa haske ya hau ya sauka. Amma samfurin yana da maɓallai da yawa — juyawar tauraron, filin maganaɗisunsa, tsarin faifan, saurin da gas ke faɗowa. Dacewa mai kyau ta tabbatar ne kawai cewa hoton zai iya aiki, ba wai dole ne ya zama haka ba.

Doka ba tare da maɓallai ba

Tare da Hang Yu, na Jami’ar Jihar Montana (Montana State University), ƙungiyar ta tuɓe samfurin har ya rage zuwa zato huɗu da kowace sigarsa ke tarayya a kai: yadda raurawar ta dogara da gefen ciki na faifan da kuma juyawar tauraron; inda iskar magnetar (wind) ke daidaita da matsin faifan; yadda gas mai faɗowa ke raguwa da lokaci; da yadda tauraron ke rage gudu.

Daga waɗannan kaɗai, adadi biyu da ake iya aunawa — saurin da ƙarar ke ƙara sauri, da saurin da injin ke dushewa — dole su kasance a kan layi madaidaici, ko menene ƙimomin da ba a sani ba. Kuma wannan layin yana tilasta wani hasashe. Muddin matsin faifan yana raguwa da sauri fiye da iskar magnetar, faifan yana jan jiki zuwa ciki kuma raurawar tana ƙara sauri. Da zarar injin ya fara dushewa da sauri, iskar tana tura faifan baya zuwa waje kuma raurawar tana rage gudu. Dole ne ƙarar ta tsaya, sannan ta juya baya.

Yaushe? Ranar ta dogara ne galibi kan lokacin raguwar juyawar magnetar — wato lokacin da yake ɗauka kafin ya rasa babban kaso na gudun juyawarsa, kwanaki 87 ± 11, wanda aka karanta daga sashen layin haske mai santsi, ba tare da dogaro da tuddan ba. Ta amfani da ƙarar da aka buga da wannan lokaci kawai, dangantakar ta yi hasashen juyawa kusan rana ta 133 a cikin tsarin lokacin supernova kanta (agogonta na kanta, wanda aka gyara saboda miƙewar lokaci da nisan sararin samaniya ke haifarwa da kuma jinkirin hasken wajen fita daga cikin tarkacen), kusan rana ta 150 kamar yadda ake gani daga Duniya, sannan tuddai da ke ƙara nisa da juna. Layi madaidaici da aka ja ta lokutan farko ya faɗi akasin haka: raurawar za ta ci gaba da ƙara sauri har sai lokacin zagayenta (period) ya kai sifili, kusan rana ta 180.

Juyawar

Daga nan ƙungiyar ta bincika ƙarin abubuwan lura 109 daga na’urorin hangen nesa na Las Cumbres Observatory, har zuwa rana ta 262, tare da bayanai daga binciken sararin samaniya na ATLAS. Bayan rana ta 170, layin haske ya nuna sababbin kololuwa da kwaruruka biyar — kuma suna ƙara nisa da juna. A cikin taswirar lokaci da mitoci (time–frequency map), babban kari yana hawa daga kimanin zagaye 0.025 a kowace rana zuwa 0.07, sannan a fili ya koma ƙasa.

Layin hasken SN 2024afav (A), tuddanta bayan an cire raguwar mai santsi (B), da karinsu a tsawon lokaci (C): mitar tana hawa, sannan tana sauka bayan kimanin rana ta 160. — Hoto na 2, Farah, Prust & Yu (2026), arXiv:2610.39240.

Ƙarar ta juya baya a rana ta 147 ± 3 kamar yadda ake gani daga Duniya — kwanaki 132 ± 3 a cikin tsarin lokacin supernova, wanda ya dace da 133 da aka yi hasashe. Bayan haka, lokacin zagayen ya tsawaita daga kimanin kwanaki 23 zuwa kimanin 35. Lokacin zagayen yana ƙaruwa da kimanin kwana 0.28 a kowace rana da ta wuce (± 0.12), daidai a tsakiyar kewayon da aka yi hasashe. An kawar da ci gaban layi madaidaici da fiye da sigma 5 nesa ba kusa ba, matakin da a cikinsa kusan babu yiwuwar hakan ya faru kwatsam.

Lokutan zagayen ƙarar farko (shuɗi) da na sabuwar “ƙarar juyawa” (antichirp, lemu), idan aka kwatanta da hasashen da aka yi daga ƙarar kaɗai (zirin shuɗi) da ci gaban layi madaidaici (mai ɗigo-ɗigo). — Hoto na 3, Farah, Prust & Yu (2026), arXiv:2610.39240.

Ba bawo-bawon iskar gas kawai ba

Bakan haske (spectra) na SN 2024afav sun nuna alamun iskar gas da ke kewaye, don haka mai yiwuwa tana nan. Amma marubutan suna jayayya cewa ba ita ce ke ƙayyade karin ba. Sun kwaikwayi kimanin layukan haske 50,000 na bazata masu hayaniya, waɗanda aka daidaita bisa wasu supernovae masu haske fiye da kima guda shida masu tuddai: ƙasa da 0.1% ne suka kai matuƙar SN 2024afav. Bawo-bawon iskar gas za su buƙaci tazarori da ke fara raguwa sannan su faɗaɗa, ba tare da wani abu da zai ɗaure sauyin da rana ta 150 ba. Kuma karo da bawo-bawon yana haifar da tuddai marasa daidaito, masu hawa da sauri suna dushewa a hankali, alhali waɗannan suna kama da raƙumin ruwa (wave) mai santsi.

Karanta faifan

Dangantakar ba ta yarda da layi ɗaya kawai ba, sai ɗan gajeren jerin layuka, ɗaya ga kowane irin faifai da kowace hanyar raurawa; gangaren da aka auna ne ke zaɓa a cikinsu. A 11.6 ± 1.6, ya fi duk wani siririn faifai da ke sanyi ta hanyar fitar da zafinsa ta haskakawa tsayi. Maimakon haka yana nuni ga wata kwararar ciki mai zafi da ke riƙe zafinsa kuma yana rasa nauyi ta hanyar iskoki — kuma, a cikin dalilai uku da ake zato na raurawar, ya faɗa kusan daidai a kan wanda ake kira juyawar kai ta Lense–Thirring (Lense–Thirring precession; raurawar da ke faruwa saboda tauraro mai juyawa yana jan sararin da ke kewaye da shi), yayin da ya kawar da lanƙwasar maganaɗisu (magnetic warping).

Binciken sararin samaniya masu zuwa ya kamata su kama ƙarin supernovae masu ƙarar tsuntsu. Kowace ko dai za ta faɗa a kan ɗaya daga cikin layukan da dangantakar ta yarda da su, tana bayyana hanyar raurawarta nan take, ko kuma, kamar SN 2024afav, ta bayyana wani abu game da faifan da ke ciyar da injinta.