Fomalhaut b<\/a>, now appears to be a dust cloud masquerading as a planet \u2014 the result of colliding planetesimals.<\/p>\nWhile searching for Fomalhaut b in recent Hubble observations, Dr. Kalas and co-authors were surprised to find a second point of light at a similar location around the star.<\/p>\n
They call this object circumstellar source 2 (cs2), while the first object is now known as cs1.<\/p>\n
\u201cThis is certainly the first time I\u2019ve ever seen a point of light appear out of nowhere in an exoplanetary system,\u201d Dr. Kalas said.<\/p>\n
\u201cIt\u2019s absent in all of our previous Hubble images, which means that we just witnessed a violent collision between two massive objects and a huge debris cloud unlike anything in our own Solar System today. Amazing!\u201d<\/p>\n
Why astronomers are seeing both of these debris clouds so physically close to each other is a mystery.<\/p>\n
If the collisions between asteroids and planetesimals were random, cs1 and cs2 should appear by chance at unrelated locations.<\/p>\n
Yet, they are positioned intriguingly near each other along the inner portion of Fomalhaut\u2019s outer debris disk.<\/p>\n
Another mystery is why scientists have witnessed these two events within such a short timeframe.<\/p>\n
\u201cPrevious theory suggested that there should be one collision every 100,000 years, or longer. Here, in 20 years, we\u2019ve seen two,\u201d Dr. Kalas said.<\/p>\n
\u201cIf you had a movie of the last 3,000 years, and it was sped up so that every year was a fraction of a second, imagine how many flashes you\u2019d see over that time.\u201d<\/p>\n
\u201cFomalhaut\u2019s planetary system would be sparkling with these collisions.\u201d<\/p>\n
Collisions are fundamental to the evolution of planetary systems, but they are rare and difficult to study.<\/p>\n
\u201cThe exciting aspect of this observation is that it allows researchers to estimate both the size of the colliding bodies and how many of them there are in the disk, information which is almost impossible to get by any other means,\u201d said Dr. Mark Wyatt, an astronomer at the University of Cambridge.<\/p>\n
\u201cOur estimates put the planetesimals that were destroyed to create cs1 and cs2 at just 30 km in size, and we infer that there are 300 million such objects orbiting in the Fomalhaut system.\u201d<\/p>\n
\u201cThe system is a natural laboratory to probe how planetesimals behave when undergoing collisions, which in turn tells us about what they are made of and how they formed.\u201d<\/p>\n
The results<\/a> appear this week in the journal Science.<\/p>\n_____<\/p>\n
Paul Kalas et al. 2025. A second planetesimal collision in the Fomalhaut system. Science, published online December 18, 2025; doi: 10.1126\/science.adu6266<\/p>\n","protected":false},"excerpt":{"rendered":"Fomalhaut \u2014 the 18th brightest star visible in night sky \u2014 is orbited by a compact source, Fomalhaut…\n","protected":false},"author":2,"featured_media":203157,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[35827,107094,9235,10805,107095,107096,107097,107098,5621,61,60,91,86234,82,247,9315],"class_list":["post-203156","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-debris","tag-debris-belt","tag-dust","tag-esa","tag-fomalhaut","tag-fomalhaut-b","tag-fomalhaut-cs1","tag-fomalhaut-cs2","tag-hubble","tag-ie","tag-ireland","tag-nasa","tag-planetesimal","tag-science","tag-space","tag-star"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/203156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=203156"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/203156\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/203157"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=203156"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=203156"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=203156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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