--- title: "Silicon Shining Brighter Than the Sun: One of the Hottest Repetitive Novas Explodes in the Large Magellanic Cloud" description: "Astronomers recorded one of the most powerful repetitive nova explosions, LMC68, in the Large Magellanic Cloud. Spectra revealed anomalously hot gas and silicon shining 95 times brighter than the Sun." date: 2026-08-24T05:14:00.000Z lang: en url: https://xab.info/en/posts/silicon-brighter-than-sun-repetitive-nova-lmc68-large-magellanic-cloud tags: [astronomy, nova, large-magellanic-cloud, white-dwarf, telescope] publisher: "XAB.info" --- # Silicon Shining Brighter Than the Sun: One of the Hottest Repetitive Novas Explodes in the Large Magellanic Cloud ![Artist's rendering of a recurrent nova in the Large Magellanic Cloud: a companion star feeds matter onto a white dwarf with a hot accretion disk](https://xab.info/media/2026/08/24/vzryv-povtornoy-novoy-lmc68-v-bolshom-magellanovom-oblake/vzryv-povtornoy-novoy-lmc68-v-bolshom-magellanovom-oblake-1.webp) ## 🎯 Key Points - A team led by Aneuryn Evans (University of the West of England) recorded a powerful repetitive nova explosion, LMC68, in the Large Magellanic Cloud. - The LMC68 system (white dwarf + red subgiant) explodes on a four-year cycle; the latest outburst occurred in August 2024. - Spectra from Chile showed the dominance of highly ionized silicon and the absence of sulfur, phosphorus, calcium, and aluminum lines. - The silicon line in the near-IR shone almost 95 times brighter than the combined radiation of the Sun; modeling yielded a gas temperature of about 3 million °C. - The causes are the low metallicity of the LMC and shock heating; this is the first direct confirmation of the latter mechanism outside the Milky Way. An international team of astronomers led by Aneuryn Evans of the University of the West of England (United Kingdom) has recorded one of the most powerful repetitive nova explosions outside the Milky Way. The observed object is the stellar system LMC 1968-12a, also known as LMC68, located in the Large Magellanic Cloud — a satellite galaxy of our own. Unlike supernovae, which completely destroy a star, novae occur in binary systems where a dense white dwarf gradually pulls matter onto itself from a giant companion. When a critical mass accumulates on its surface, a thermonuclear explosion occurs, after which the cycle begins anew. It is precisely this "repeatability" that makes LMC68 a particularly valuable object for studying the physics of explosions. ### An Explosion on Schedule: How the LMC68 System Works The LMC68 system consists of a white dwarf and a red subgiant and is characterized by a predictable four-year cycle of outbursts: explosions were recorded in 1968, 1990, 2002, 2010, 2016, and 2020. The latest outburst occurred exactly on schedule in August 2024, allowing the scientists to prepare the observational campaign in advance. At the same time, as the researchers note, LMC68 is located about 50 times farther away than novae in our galaxy, so its visual brightness is 2,500 times fainter than that of nearby analogues — which makes the spectra obtained all the more valuable. ### Observations in Chile: Spectra Lacking the Usual Elements The team used the Magellan Baade telescope and the Gemini South observatory in Chile to obtain near-infrared spectra 9 and 22 days after the outburst. The data obtained surprised the researchers: the spectrum almost completely lacked the lines of sulfur, phosphorus, calcium, and aluminum that are typical of such explosions. Instead, a single intense signal from highly ionized silicon, stripped of nine of its fourteen electrons, dominated. Co-author of the study Thomas Geballe called this picture an "unprecedented phenomenon." ### Silicon Shining Brighter Than the Sun During the first observations, the line of ionized silicon in the near-infrared range shone almost 95 times brighter than the combined radiation of the Sun across all wavelengths. Computer modeling showed that the temperature of the ejected gas reached approximately three million degrees Celsius, making LMC68 one of the hottest novae ever recorded by astronomers. It is important to clarify the context of this figure: it refers specifically to the radiation of a single silicon spectral line in the near-infrared range, not to the total visible brightness of the entire star. ### Why the Explosion Was So Hot Scientists highlight two key factors. The first is low metallicity: stars in the Large Magellanic Cloud contain fewer heavy elements than those in the Milky Way. Since heavy elements usually retain heat and promote earlier explosions, their scarcity forces more material to accumulate before detonation, making the final explosion more powerful. The second factor is shock heating: the expanding gas shell from the explosion collided with the outer atmosphere of the massive red subgiant, forming powerful shock waves that further heated the gas. ### Significance for Astrophysics The data obtained constitute the first direct observational confirmation of the shock-heating mechanism in a nova explosion outside our galaxy. This allows astronomers to more accurately calibrate models of thermonuclear explosions in binary systems and better understand how the metallicity of the environment affects the energetics and spectral signatures of novae. Further observations of subsequent LMC68 outbursts, expected on the four-year cycle, should help test the robustness of the derived patterns. ## 🔍 Fact-Check Verification - [Shining 95 Times Brighter Than the Sun: An Anomalous Stellar Explosion Occurred in a Neighboring Galaxy](https://www.rbc.ua/ukr/news/syae-95-raziv-skravishe-sontse-susidniy-galaktitsi-1787322189.html) - Заголовок и тема совпадают с основой: аномальный взрыв в соседней галактике, яркость в 95 раз выше Солнца. Подтверждает ключевой тезис о кремниевой линии. - [One of the Largest Known Stars Has Changed Color: We May See a Very Bright Explosion (Photo)](https://focus.ua/technologies/745013-odna-iz-krupneyshih-izvestnyh-zvezd-izmenila-cvet-my-mozhem-uvidet-ochen-yarkiy-vzryv-foto) - Касается яркого взрыва/изменения цвета звезды в LMC, но, судя по теме, относится к другому объекту (WOH G64), а не к LMC68. Использован только как общий контекст по активности LMC. - [Astronomers Expect a Bright Rebirth of Star WOH G64 in the Large Magellanic Cloud Galaxy](https://overclockers.ru/blog/kosmos_news/show/250455/Astronomy-ozhidajut-moschnogo-razrusheniya-zvezdy-WOH-G64-v-galaktike-Bol-shoe-Magellanovo-Oblako) - Прямо указывает на объект WOH G64, то есть на другую звезду LMC, не на LMC68. Не подтверждает факты о LMC68; принят лишь как фоновый контекст по галактике. ## ❓ FAQ ### Q: What is a repetitive nova and how does it differ from a supernova? **A:** A repetitive nova occurs in a binary system where a white dwarf pulls matter from its companion and periodically explodes without being completely destroyed. A supernova, by contrast, completely destroys the star. ### Q: Where is LMC68 located and how often does it explode? **A:** LMC68 (LMC 1968-12a) is located in the Large Magellanic Cloud. It explodes on a four-year cycle: outbursts were recorded in 1968, 1990, 2002, 2010, 2016, 2020, and 2024. ### Q: What does "shining 95 times brighter than the Sun" mean? **A:** It means that the line of highly ionized silicon in the near-infrared range shone almost 95 times brighter than the combined radiation of the Sun across all wavelengths, not that the visible brightness of the entire star was that high. ### Q: Why was the explosion so hot? **A:** Because of the low metallicity of the Large Magellanic Cloud (more material accumulates before detonation) and shock heating: the explosion shell collided with the atmosphere of the red subgiant, heating the gas to approximately three million degrees Celsius.