{"id":225403,"date":"2025-09-14T05:36:19","date_gmt":"2025-09-14T05:36:19","guid":{"rendered":"https:\/\/www.europesays.com\/us\/225403\/"},"modified":"2025-09-14T05:36:19","modified_gmt":"2025-09-14T05:36:19","slug":"like-nothing-anyone-has-ever-seen-before-bizarre-supernova-stuns-scientists","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/225403\/","title":{"rendered":"\u201cLike Nothing Anyone Has Ever Seen Before\u201d \u2013 Bizarre Supernova Stuns Scientists"},"content":{"rendered":"

\t\t\"Supernova<\/a>For the first time, astronomers have seen the inner layers of a star revealed in its final moments. The finding suggests a new, more violent pathway for how massive stars die. Credit: Shutterstock<\/p>\n

A distant supernova exposed elements from a star\u2019s core. The result reshapes ideas of how massive stars evolve.<\/strong><\/p>\n

According to long-standing theory, stars are built in layers like onions, with each layer composed of different elements that grow heavier toward the core. While this model is widely accepted, directly observing a star\u2019s deeper layers has been nearly impossible.<\/p>\n

Until now.<\/p>\n

Astronomers using the Keck Observatory in Hawaii have collected spectroscopic data from a supernova first identified by the Zwicky Transient Facility in 2021. The event, designated SN 2021yf, occurred 2.2 billion light-years away. The Keck observations revealed ionized silicon, sulfur, and argon, elements never before detected in a supernova because they are normally hidden beneath outer layers.<\/p>\n

\"Spectral<\/a>This figure shows the elements detected in the spectrum from SN 2021yf with the Keck\u2019s Low Resolution Imaging Spectrometer one day after the ZTF spotted it. \u201cThe spectrum reveals narrow emission lines of highly ionized species of silicon, sulfur, and argon, which have never been seen in any SN before, as well as doubly ionized carbon, singly ionized magnesium, and neutral helium,\u201d the authors write. The observations also show that some of these elements are moving at about 3,000 km\/sec in an ejected circumstellar medium. Credit: Schulze et al. 2025
\nConfirming and challenging theory<\/p>\n

The finding supports some theoretical predictions about the structure of exploding stars but also raises new challenges.<\/p>\n

It is well established that massive stars shed material from their outer layers as they near the point of collapse into a supernova. This process has been documented many times, and the new data confirm it again. However, SN 2021yf appears to have lost far more material than any star observed before, leaving astronomers to reconsider how extreme this stripping process can be.<\/p>\n

The observations are presented in a new paper titled \u201cA cosmic formation site of silicon and sulfur revealed by a new type of supernova explosion.\u201d The lead author is Steve Schulze, a research associate at Northwestern University\u2019s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA).<\/p>\n

\u201cThis is the first time we have seen a star that was essentially stripped to the bone,\u201d said lead author Schulze. \u201cIt shows us how stars are structured and proves that stars can lose a lot of material before they explode. Not only can they lose their outermost layers, but they can be completely stripped all the way down to the core and still produce a brilliant explosion that we can observe from very, very far distances.\u201d<\/p>\n

\"Illustration<\/a>Artist\u2019s illustration of the supernova\u2019s aftermath. Even after the star was stripped down to its core, it continued to experience violent mass-loss episodes, ejecting shells of material rich in silicon (grey), sulfur (yellow), and argon (purple). The catastrophic collision of these massive shells, as depicted in this illustration, generated a brilliant supernova explosion visible across 2.2 billion light-years of space. Credit: Keck Observatory\/Adam Makarenko<\/p>\n

When astronomers study supernovae, the most prominent signals usually come from light elements such as hydrogen and helium. If these outer layers have already been stripped away, signatures of carbon, oxygen, neon, and magnesium may also become visible. The deeper shells, which contain heavier elements like silicon, sulfur, and argon, generally remain hidden from view.<\/p>\n

For decades, stellar theory has described massive stars as being structured in concentric layers, much like the rings of an onion. The new Keck data provide striking confirmation of this model. By revealing the star\u2019s inner composition just before its explosion, these observations offer the clearest evidence yet in direct support of the layered structure predicted by theory.<\/p>\n

\"Illustration<\/a>When astronomers spotted this supernova, its lighter outer layers were stripped away. For the first time, they saw a supernova\u2019s inner layers made of heavier elements usually hidden from view. Credit: W.M. Keck Observatory\/Adam Makarenko
\nUnexpected mass loss<\/p>\n

However, the observations also pose a challenge. Astrophysicists know that massive stars eject material before exploding as supernova. Shock waves from the expelled matter interact with the surrounding medium, heating it and creating observable light signatures. But SN 2021yf must have ejected much more material than thought possible, because it\u2019s stripped down to its core.<\/p>\n

\u201cThis event quite literally looks like nothing anyone has ever seen before,\u201d added Adam Miller, an assistant professor of physics and astronomy at Northwestern and senior author on the study. \u201cThis star is telling us that our ideas and theories for how stars evolve are too narrow. It\u2019s not that our textbooks are incorrect, but they clearly do not fully capture everything produced in nature. There must be more exotic pathways for a massive star to end its life that we hadn\u2019t considered.\u201d<\/p>\n

\"Table<\/a>This table shows supernova taxonomy. SN 2021yf could be a new type called Type Ien. The \u2018e\u2019 signifies the position of the silicon\/sulfur layer in the star\u2019s structure, and the \u201cn\u201d signifies that the emission lines are narrow. Credit: Wikipedia<\/p>\n

Massive stars have the power to fuse lighter elements into heavier elements in a process called nucleosynthesis. (Without stellar nucleosynthesis, the only elements in the Universe would be those created during the Big Bang.) Throughout its life of fusion, a massive star burns lighter elements like hydrogen and helium in its outer shells, while in its core it burns successively heavier elements in its deeper layers. Eventually, a star ends up with an iron core. Iron can\u2019t be burned to release more energy, so once the core is dominated by iron, fusion virtually ceases. Without the outward pressure from fusion, the star collapses in on itself and explodes as a supernova.<\/p>\n

Seeing the hidden layers<\/p>\n

Astrophysicists have observed layers of helium, carbon, and oxygen in exploding stars before, which are visible after the star has ejected its outer layer of hydrogen. By observing the silicon, sulfur, and argon, it means that this star has ejected not only its outer helium layer, but other layers as well. This likely happened in multiple episodes rather than all at once.<\/p>\n

\u201cStars experience very strong instabilities,\u201d Schulze said. \u201cThese instabilities are so violent that they can cause the star to contract. Then, it suddenly liberates so much energy that it sheds its outermost layers. It can do this multiple times.\u201d<\/p>\n

Alex Filippenko is a professor of astronomy at UC Berkeley and a co-author of the paper. He happened to be working with the Keck when SN 2021yf was discovered, and quickly pivoted to capture its spectrum withe the Keck\u2019s LRIS. \u201cIt\u2019s so exciting to discover a new class of exploding star, especially one that provides a confirmation of some of our theories of how massive stars evolve with time yet also reveals interesting new puzzles,\u201d said Filippenko. \u201cIt was very fortunate that my team was using the Keck I telescope the night SN 2021yfj was discovered \u2014 we were able to obtain a spectrum that directly led to the realization that this was an incredibly special new type of supernova. Opportunities of this kind are rare!\u201d<\/p>\n

Toward a new supernova type<\/p>\n

The silicon, sulfur, and argon in the star weren\u2019t always present. These elements were created via nucleosynthesis in the star\u2019s interior as it approached the end of its life.<\/p>\n

\u201cThis star lost most of the material that it produced throughout its lifetime,\u201d Schulze said. \u201cSo, we could only see the material formed during the months right before its explosion. Something very violent must have happened to cause that.\u201d<\/p>\n

That question is at the heart of this discovery. Is SN 2021yfj a new type of supernova defined by a powerful new process that stripped it of its outer layers? Some of the explanations the team is considering are interactions with a companion star, unusual and extremely powerful stellar winds, and a massive eruption that preceded the supernova explosion.<\/p>\n

Rethinking stellar explosions<\/p>\n

\u201cMassive stars can lose a substantial amount of their birth mass through stellar winds, eruptions, and interaction with a companion star,\u201d the researchers write in their paper. The presence of helium in this star\u2019s circumstellar material is puzzling, since helium is usually ejected earlier in the SN process. \u201cSince massive stars tend to live in binary systems, it may not be too unlikely to have a helium-star companion with a strong wind,\u201d they write. This could explain the helium.<\/p>\n

The researchers think that the most likely explanation is that this massive star simply tore itself apart. Stellar cores of massive stars are under intense gravitational pressure that raises their core temperatures until nuclear fusion is reignited, generating a powerful explosion. The explosion blasts away the star\u2019s outer layers. The process is repetitive, and each time it happens, more material is ejected until the deeper core is visible.<\/p>\n

Supernovae are classified according to spectroscopy, and classifications are centered on hydrogen. Type 1 show helium but no hydrogen and Type 2 show hydrogen. Then there are sub-types under each of those classifications based on other spectral lines. The sequence of labelled sub-types reflects the amount of stripping in the progenitor stars.<\/p>\n

First of its kind<\/p>\n

\u201cOur observations \u2026 suggest that SN 2021yfj is indeed the first example of a Type Ien SN,\u201d the researchers write in their paper. This is a new type that lacks lines from hydrogen or helium, and is instead dominated by emission lines from highly ionized silicon, sulfur, and argon.<\/p>\n

Since there\u2019s only one example of this type, there are still many questions. As is often the case in astronomy, a larger dataset will likely lead to some answers.<\/p>\n

\u201cWhile we have a theory for how nature created this particular explosion,\u201d Miller said, \u201cI wouldn\u2019t bet my life that it\u2019s correct, because we still only have one discovered example. We still don\u2019t fully understand how nature created this particular explosion. This star underscores the need to uncover more of these rare supernovae, so we can continue to study them.\u201d<\/p>\n

Reference: \u201cA cosmic formation site of silicon and sulphur revealed by a new type of supernova explosion\u201d by Steve Schulze, Avishay Gal-Yam, Luc Dessart, Adam A. Miller, Stan E. Woosley, Yi Yang, Mattia Bulla, Ofer Yaron, Jesper Sollerman, Alexei V. Filippenko, K-Ryan Hinds, Daniel A. Perley, Daichi Tsuna, Ragnhild Lunnan, Nikhil Sarin, Sean J. Brennan, Thomas G. Brink, Rachel J. Bruch, Ping Chen, Kaustav K. Das, Suhail Dhawan, Claes Fransson, Christoffer Fremling, Anjasha Gangopadhyay, Ido Irani, Anders Jerkstrand, Nikola Knezevic, Doron Kushnir, Keiichi Maeda, Kate Maguire, Eran Ofek, Conor M. B. Omand, Yu-Jing Qin, Yashvi Sharma, Tawny Sit, Gokul P. Srinivasaragavan, Nora L. Strothjohann, Yuki Takei, Eli Waxman, Lin Yan, Yuhan Yao, WeiKang Zheng, Erez A. Zimmerman, Eric C. Bellm, Michael W. Coughlin, Frank. J. Masci, Josiah Purdum, Mickael Rigault, Avery Wold and Shrinivas R. Kulkarni, 3 September 2024, arXiv.
DOI: 10.48550\/arXiv.2409.02054<\/a><\/p>\n

Adapted from an article originally published on Universe Today<\/a>.<\/p>\n

Never miss a breakthrough: Join the SciTechDaily newsletter.<\/a><\/b><\/p>\n","protected":false},"excerpt":{"rendered":"For the first time, astronomers have seen the inner layers of a star revealed in its final moments.…\n","protected":false},"author":3,"featured_media":225404,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[4514,28891,121967,159,56332,95792,67,132,68,121968],"class_list":{"0":"post-225403","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-astronomy","9":"tag-astrophysics","10":"tag-interstellar-wind","11":"tag-science","12":"tag-stellar-evolution","13":"tag-supernova","14":"tag-united-states","15":"tag-unitedstates","16":"tag-us","17":"tag-w-m-keck-observatory"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115201034693564129","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/225403","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=225403"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/225403\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/225404"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=225403"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=225403"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=225403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}