{"id":219810,"date":"2025-12-07T08:06:07","date_gmt":"2025-12-07T08:06:07","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/219810\/"},"modified":"2025-12-07T08:06:07","modified_gmt":"2025-12-07T08:06:07","slug":"seeing-stellar-explosions-in-high-definition","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/219810\/","title":{"rendered":"Seeing stellar explosions in high definition"},"content":{"rendered":"

An international team of astronomers, including researchers from the University of Michigan, has captured unprecedented images of two stellar explosions<\/a>\u2014known as novae\u2014within days of their eruption.<\/strong><\/p>\n

\"Images<\/a><\/p>\n

Images of Nova Herculis 2021 (V1674 Her) taken with the CHARA Array, two and three days after the eruption began. The images show two outflows expanding in nearly perpendicular directions, forming an hourglass-like structure consistent with theoretical predictions, which are illustrated in the rightmost artistic impression. Image credit: CHARA Array\/NASA GSFC<\/p>\n

Catching these novae so early in the act provides new evidence that such explosions are more complex than previously thought.<\/p>\n

The study, published in the journal Nature Astronomy, used a technique called interferometry at the Center for High Angular Resolution Astronomy, or CHARA, Array in California. This approach allowed scientists to combine the light from multiple telescopes, achieving the sharp resolution needed to directly image the rapidly evolving explosions.<\/p>\n

\u201cThese aren\u2019t the first novae to be imaged, but there haven\u2019t been very many,\u201d said\u00a0John Monnier<\/a>, a co-author of the new study and U-M professor of astronomy. \u201cWe\u2019re showing that we\u2019re getting better at taking these images and making it easier to do so.\u201d<\/p>\n

The study was funded by NASA, and the CHARA Array was created with support from the U.S. National Science Foundation. Instruments used on the study\u2014namely, the MIRC-X and MYSTIC beam combiners\u2014were also created with support from the NSF and the European Research Council in collaboration with the University of Exeter.<\/p>\n

Novae occur in systems with two large celestial bodies: a \u201cregular\u201d star and a white dwarf, which is the hot, compact core of a previously much larger star. The white dwarf steals material from its companion star until it accrues enough to detonate a runaway nuclear reaction on its surface. Until recently, astronomers could only infer the early stages of these eruptions indirectly, because the expanding material appeared as a single unresolved point of light.<\/p>\n

\u201cInstead of seeing just a simple flash of light, we\u2019re now uncovering the true complexity of how these explosions unfold. It\u2019s like going from a grainy black-and-white photo to high-definition video,\u201d said\u00a0Elias Aydi<\/a>, lead author of the study and assistant professor of physics and astronomy at Texas Tech University. \u201cThese observations allow us to watch a stellar explosion in real time, something that is very complicated and has long been thought to be extremely challenging.\u201d<\/p>\n

The best there is at what they do<\/p>\n

The U-M contingent of the team helped develop the software and hardware to combine light from the multiple telescopes in the array. The resolution of the image produced by the array is determined by the separation between its constituent telescopes, compared with more conventional telescopes that have a resolution determined by the size of their mirrors.<\/p>\n

For comparison, the JWST space telescope uses a 20-foot-plus mirror to produce its stunning images. Meanwhile, CHARA\u2019s telescopes are separated by 300 yards.<\/p>\n

\u201cIn terms of resolution, we have the imaging ability of a telescope that\u2019s three football fields across,\u201d Monnier said. \u201cIt\u2019s the world\u2019s highest resolution in that regard, so we\u2019re making the best images you can make using these facilities.\u201d<\/p>\n

The team used this technique to image two different novae that erupted in 2021. One, Nova V1674 Herculis, was among the fastest on record, brightening and fading in just days. Images revealed two distinct, perpendicular outflows of gas\u2014evidence that the explosion was powered by multiple interacting ejections.<\/p>\n

The second, Nova V1405 Cassiopeiae, evolved much more slowly. It held onto its outer layers for more than 50 days before finally ejecting them, providing the first clear evidence of a delayed expulsion. When the material was finally expelled, new shocks were triggered.<\/p>\n

The team was able to develop and verify these interpretations using data from other observatories, including the International Gemini Observatory and NASA\u2019s Fermi Large Area Telescope.<\/p>\n

\u201cNovae are more than fireworks in our galaxy\u2014they are laboratories for extreme physics,\u201d said\u00a0Laura Chomiuk<\/a>, a co-author from Michigan State University and an expert on stellar explosions. \u201cBy seeing how and when the material is ejected, we can finally connect the dots between the nuclear reactions on the star\u2019s surface, the geometry of the ejected material and the high-energy radiation we detect from space.\u201d<\/p>\n

The findings challenge the long-held view that nova eruptions are single, impulsive events. Instead, they point to a variety of ejection pathways, including multiple outflows and delayed envelope release, reshaping our understanding of these cosmic blasts.<\/p>\n

\u201cThis is just the beginning,\u201d Aydi said. \u201cWith more observations like these, we can finally start answering big questions about how stars live, die and affect their surroundings. Novae, once seen as simple explosions, are turning out to be much richer and more fascinating than we imagined.\u201d<\/p>\n

Source: University of Michigan<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"An international team of astronomers, including researchers from the University of Michigan, has captured unprecedented images of two…\n","protected":false},"author":2,"featured_media":219811,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[18,19,17,133],"class_list":{"0":"post-219810","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-eire","9":"tag-ie","10":"tag-ireland","11":"tag-science"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115677258619332545","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/219810","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=219810"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/219810\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/219811"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=219810"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=219810"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=219810"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}