SUPERNOVA DA TA ƊAUKI KWANA 88 KAFIN TA KAI ƘOLOLUWA

Supernova 1987A ta koya wa masana ilimin taurari cewa tauraro mai yawan hydrogen zai iya fashewa sannan ya ɗauki lokacinsa: maimakon ya haskaka cikin ’yan kwanaki, ya ƙara haske a hankali na kusan kwana 100. Ta zama samfurin farko na wani ƙaramin iyali, supernovae “masu kama da 87A” — kusan 30 aka sani, kusan kashi 1.4% na dukkan taurari masu rushewa.

A shekarun nan, manyan binciken sararin sama sun gano wasu ’yan mambobi masu tsanani na wannan iyali, masu haske sosai kuma masu daɗewa fiye da sauran. Yana da wuya a bayyana su da hanyar da aka saba, inda neutrinos daga sabon tauraron neutron da aka haifa ke tarwatsa tauraron.

Wani ƙato mai jinkiri

A ranar 11 ga Mayu 2023, Zwicky Transient Facility a California ta hango wani sabon tushe a cikin wani ƙaramin galaxy a redshift 0.1020, kusan megaparsec 485 nesa, wato shekarun haske biliyan 1.6. Mai suna SN 2023iop, wata ƙungiyar ƙasa da ƙasa ƙarƙashin jagorancin Steve Schulze, na Weizmann Institute of Science a Isra’ila, ta bi ta fiye da kwana 600, da na’urorin hangen nesa daga ultraviolet zuwa raƙuman rediyo.

• Ta ɗauki aƙalla kwana 88 kafin ta kai ƙololuwarta — ainihin hawan ya fi tsawo, tunda an kama ta tana kan hawa tuni.
• A ƙololuwa ta kai magnitude na gaske (absolute magnitude) na −20.1: kusan magnitude 0.9 fiye da mai riƙe da tarihin baya na iyalinta, OGLE-73, kuma magnitude 3.7 zuwa 4.0 fiye da SN 1987A. A wannan ma’auni, ƙasa yana nufin ƙarin haske, kuma kowane magnitude yana daidai da kusan ninki 2.5.
• Ta fitar da haske na aƙalla erg 4.3 × 10⁵⁰, watakila kusa da 10⁵¹ — erg ƙaramin ma’auni ne na makamashi, duk da haka hakan shi ne abin da Rana ke fitarwa a cikin ’yan biliyoyin shekaru.
• Spectrum ɗinta suna kama da na supernova ta yau da kullum mai yawan hydrogen — amma suna canzawa a hankali matuƙa. Kusan shekara ɗaya bayan ƙololuwa, SN 2023iop ba ta riga ta shiga matakin da ambulan ɗin tauraron ke zama mai haskakawa ya bar layukan tsakiyar su bayyana ba, matakin da SN 1987A ta kai a cikin kusan kwana 100.

SN 2023iop (baƙi) idan aka kwatanta da SN 1987A, SN 2018hna, al’amuran masu tsanani OGLE-73 da SN 2020faa, da supernovae masu kama da 87A daga binciken ZTF (toka): ta fi su duka haske da faɗi. — Figure 18, Schulze et al. (2026), arXiv:2610.27312.

Makamashi ya yi yawa ga neutrinos

Fashewa da neutrinos ke tuƙawa tana da kasafin kuɗi ƙayyadadde: sabon tauraron neutron yana fitar da kusan erg 3 × 10⁵³, kwaikwayo suna mayar da kusan kashi 1% na shi zuwa motsi, kuma supernova ta yau da kullum tana fitar da haske na kusan erg 10⁴⁹ kawai. Don ya dace da SN 2023iop, dole duk jerin ya kasance kusan ninki 50 mafi inganci — wanda zai bayyana a matsayin abubuwan da aka harba masu ƙarin sauri ko alamun karo da iskar gas da ke kewaye. Ba a ga ko ɗaya ba.

Layin haske (light curve) yana ba da ƙarin alamu biyu. Hawan a hankali yana nuna fiye da nauyin rana 12 na abubuwan da aka harba. Kuma idan nickel-56 mai rediyo ne ya tuƙa ƙololuwar, kamar a yawancin supernovae, zai buƙaci kusan nauyin rana 2.2 na shi — fiye da abin da fashewa da neutrinos ke tuƙawa za ta iya ƙirƙira. Marubutan sun jaddada cewa wannan iyaka ce ta sama, mai inganci ne kawai idan rediyo ce ke rinjaye.

Zanen yatsan nickel

Alama mafi bayyanawa ta fito a makare. Zuwa rana ta 326 bayan ƙololuwa, wani tudu na biyu ya girma a cikin spectrum kusa da ångström 7,300, wanda babu shi har zuwa rana ta 140. Ƙungiyar ta gano shi, ba tare da tabbaci ba, a matsayin layin nickel-58 mai tsayayye, wanda ke nuna kusan nauyin rana 0.017 na shi idan iskar gas ɗin tana 5,000 K — ninki goma fiye da haka idan tana 3,000 K.

Hakan yana da muhimmanci saboda taurari masu rushewa na yau da kullum suna samar da kusan ninki goma ƙasa da haka. Ana kaiwa irin waɗannan adadi ne kawai a cikin samfuran supernovae na pair-instability waɗanda tsakiyar helium ɗinsu ya wuce nauyin rana ɗari. Wannan hanya tana buɗewa ga tsakiyar helium mai nauyin rana 65 zuwa 130: nau’i-nau’in electrons da positrons suna samuwa a can a kuɗin photons ɗin da ke ɗaukar tsakiyar; da aka ƙwace masa wannan matsi, yana rushewa, yana ɗumama, kuma haɗuwar nukiliya tana gudu ba iyaka lokaci guda, har ta isa ta wargaza dukan tauraron. Babu ɗaya daga cikin supernovae na kwatance da ke nuna wannan tudu.

Abin da ya dace, da abin da bai dace ba

Wani samfuri da aka wallafa na fashewar pair-instability ta wani babban tauraro ja (red supergiant) mai nauyin rana 190 ya dace da hawan, ƙololuwa da spectrum sosai abin mamaki — har zuwa kwana 150 bayan ƙololuwa. Sannan ya gaza: samfurin yana dushewa yayin da cobalt-56 ke ruɓewa, kusan magnitude 1 a kowane kwana 100, yayin da SN 2023iop ta dushe da magnitude 0.2 kawai a kowane kwana 100, tana ci gaba da kasancewa har magnitude 3.5 mafi haske fiye da samfurin a cikin shuɗi (0.7 a cikin ja), kuma ta fi shi shuɗi.

SN 2023iop (ɗigo baƙi) idan aka kwatanta da samfuran pair-instability biyu masu nauyin rana 190 a launuka uku: samfurin babban tauraro ja (layin ja) yana bin bayanan har zuwa kusan kwana 150 bayan ƙololuwa, sannan ya faɗi ƙasa da su. — Figure 13 (fanonin sama), Schulze et al. (2026), arXiv:2610.27312.

Ƙungiyar ta gwada sauran hanyoyi. Amon haske (light echo) — ƙura da ke mayar da ƙololuwar da ta gabata — an kawar da shi saboda santsin canjin spectrum. Abubuwan da ke faɗuwa baya a kan wani baƙin rami (black hole) ko tauraron neutron na tsakiya suna samun siffar gaba ɗaya daidai amma ba launuka ba. Karo da iskar gas da tauraron ya zubar kafin ya mutu, a ɓoye a cikin faifai, yana yiwuwa ta fannin makamashi kuma zai iya samar da hasken ƙarshe ba tare da barin siraran layukan da aka saba ba. Wasu alamu biyu suna nuna tauraro na musamman: haske mai polarization na kashi 0.8–1.0%, alamar fashewa mara daidaito, da wani ƙaramin galaxy mai masaukinta mai nauyin kusan rana miliyan 150, wanda watakila yana da ƙarancin sinadarai masu nauyi — sharaɗi ne don tauraro ya riƙe irin wannan babban tsakiya.

Gargaɗi ga sararin samaniya mai nisa

Marubutan sun kammala cewa fashewar pair-instability ita ce yanayi mafi dacewa, inda ƙarin hasken ƙarshe ke samun ƙarfi daga karo na ɓoye. Sun bayyana iyakoki a fili: gano nickel ɗin ya dogara ne a kan layin spectrum ɗaya kuma yana buƙatar tabbatarwa, kuma SN 2023iop “tana kama da tana buƙatar fiye da ɗaya” tushen ƙarfi.

Sun kuma ciro darasi ga binciken gaba. Baƙon halin SN 2023iop na ƙarshe ba zai bayyana ba a nisa mafi girma — ƙasa da hotuna guda na Rubin observatory bayan redshift 0.3, ƙasa da iyakokin binciken James Webb bayan redshift 2 zuwa 6. Idan aka gan ta daga nesa, da an lakaba mata ɗan takarar pair-instability “ba tare da wani shakku ba”. Saboda haka ’yan takara masu nisa na iya bayyana mafi tsabta fiye da yadda suke. Lura da aka amince da su da James Webb Space Telescope za su nemi ƙura da layukan infrared a SN 2023iop da za su iya bambanta yanayin.