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As the white dwarf feeds, the pair blazes far brighter than similar systems \u2013 a century-old mystery that a new study says it has finally cracked.<\/p>\n
Led by Pasi Hakala from the University of Turku<\/a> in Finland, the team used the European Southern Observatory\u2019s Very Large Telescope in Chile to probe V Sge\u2019s extreme behavior. The results point to a runaway case of \u201cstellar cannibalism.\u201d<\/p>\n White dwarf in a feeding frenzy<\/p>\n White dwarfs are the ultra-compact embers left behind when sun-like stars<\/a> exhaust their fuel. On their own, they glow faintly. Paired with a close companion, they can become voracious, as gravity from the white dwarf pulls gas \u2013 mostly hydrogen \u2013 off the neighboring star.<\/p>\n As that gas piles up, it heats to extraordinary temperatures and ignites thermonuclear burning on the dwarf\u2019s surface. <\/p>\n The study concludes that V Sge\u2019s famous overbrightness comes from this very process operating at ferocious rates. It turns the white dwarf\u2019s outer layers into a sustained, nuclear-powered beacon.<\/p>\n The V Sge system has baffled astronomers since its discovery in 1902 because it outshines its peers so dramatically. The study argues the system is in a \u201cfeeding frenzy,\u201d with mass transfer exceeding what the white dwarf can absorb.<\/p>\n Luminous halo signals instability <\/p>\n One of the team\u2019s most striking finds is a broad ring of gas \u2013 a luminous halo<\/a> encircling both stars. That ring appears to be the overflow. <\/p>\n The system rips material from the companion that the white dwarf can\u2019t accrete and flings it outward to form a circumbinary shroud.<\/p>\n The sheer energy released in the process, the researchers say, is also jostling the system, contributing to the erratic, \u201cwild\u201d motion seen in monitoring data.<\/p>\n That halo isn\u2019t just window dressing. It\u2019s a clue that V Sge is being pushed toward instability. When the inflow of fuel momentarily overwhelms the white dwarf\u2019s ability to burn it steadily, pressure can build until the surface layers detonate in a thermonuclear flash.<\/p>\n A rare outburst on the horizon<\/p>\n The team warns that V Sge is primed for a classic nova<\/a> \u2013 a powerful, but non-destructive outburst triggered when accumulated hydrogen ignites on the white dwarf\u2019s surface. <\/p>\n If that happens in the coming years, the system could brighten enough to be visible to the naked eye. It would be a rare treat for skywatchers.<\/p>\n Farther down the line, the endgame could be even more spectacular. As the stars spiral inward and the white dwarf gains mass, they may collide or reach a catastrophic limit.<\/p>\n In that scenario, V Sge would explode as a supernova<\/a> \u2013 an event so luminous it would be visible even in daylight. That fate isn\u2019t guaranteed, and it may be centuries away. But the current feeding rate and the presence of the gas ring suggest this binary is on a dangerous trajectory.<\/p>\n A star system in real time<\/p>\n For decades, astronomers struggled to explain why V Sge was the brightest system of its kind. <\/p>\n By tying its glare to sustained thermonuclear burning driven by extreme mass transfer \u2013 and by revealing the telltale, system-wide gas ring \u2013 the new study provides a coherent picture of how this oddball works.<\/p>\n It also offers a living laboratory where scientists can study how close binaries evolve and how novae trigger. It may even explain how some white dwarfs cross the threshold into supernovae.<\/p>\n Most of the time, stellar evolution<\/a> plays out slowly, across eons. V Sagittae is a rare exception: a nearby, rapidly changing system writing its next chapter in real time. Keep an eye on the southern sky. The next burst from this hungry white dwarf could be bright enough for all of us to see.<\/p>\n The research is published in the journal Monthly Notices of the Royal Astronomical Society<\/a>. <\/p>\n Image Credit: University of Southampton<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.\u00a0<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Astronomers have caught a nearby stellar duo in a dramatic act. A super-dense white dwarf star is siphoning…\n","protected":false},"author":2,"featured_media":16452,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[111,139,69,147,392],"class_list":["post-16451","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/16451","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=16451"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/16451\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/16452"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=16451"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=16451"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=16451"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}