The Webb telescope illuminates the cosmic dawn: possible traces of the first stars that formed in the very first moments of the Universe.<\/p>\n
According to a group of astronomers, the James Webb Space Telescope (JWST) may have finally observed the \u201cfirst generation of stars\u201d, which formed in the very first moments of the Universe. These \u201cprimordial stars\u201d, known as Population III or Pop IIIwould appear to reside in a remote galaxy called LAP1-B, already examined with Webb.<\/p>\n
Its light, which started over 13 billion years ago, has reached us, allowing us to see the galaxy as it was when the universe was just 800 million years old.<\/p>\n
The first time. According to the team led by Eli Visbal (University of Toledo), if confirmed, this would be the first direct detection of Pop III stars. \u00abTo find them we needed the sensitivity of the Webb\u00bb, explained Visbal, \u00aband also the multiplier effect of about 100 times given by the gravitational lens of a cluster of galaxies located between us and LAP1-B\u00bb.<\/p>\n
A look at the oldest stars. The JWST observes LAP1-B during a crucial era, called the era of reionization, when the ultraviolet radiation from the first stars began to ionize the neutral gas (hydrogen and helium) present within it, marking the end of the so-called \u201ccosmic dark age\u201d.<\/p>\n
Pop III stars would have been born even earlier, about 200 million years after the Big Bang, when the Universe had cooled enough to allow the first atoms to form. In the standard cosmological model, these stars would have formed into small \u201cclusters\u201d of dark matter, which then helped build primordial stars and galaxies.<\/p>\n
The study. Visbal, who published his research on Astrophysical Journal Lettersunderlines that studying them not only helps us understand the origin of galaxies, but could also give clues to the properties of dark matter itself: different models of dark matter, in fact, predict different scenarios for their birth.<\/p>\n
Chemical traces and mass. Pop III stars would be characterized by a \u201cvery low metallicity\u201d (it is a way of defining stars formed almost exclusively from hydrogen and helium, with very few heavier elements. In practice: \u201calmost pure\u201d stars, born when the universe was still chemically young), because they were formed from the first gases present in the primordial Universe.<\/p>\n
This makes them very different from modern stars, rich in heavier elements. This different structure would allow these stars to reach enormous masses \u2014 even 100 times that of the Sun or more \u2014 and to group into relatively small nuclei.<\/p>\n
In the case of LAP1-B, the team found nearly metal-free gas and a stellar core with total mass on the order of thousands of solar masses.<\/p>\n
Gravitational lens as an \u201camplifier\u201d. A key point of the discovery is the use of a \u201cgravitational lens\u201d, a phenomenon predicted by Einstein: the galaxy cluster MACS J0416 acts as a lens, bending and amplifying the light signal of LAP1-B. This made an object visible to Webb that would otherwise be too faint even for his eyes, pushing observation where it would never have reached.<\/p>\n
Visbal explains: \u201cThe calculations suggest that similar systems \u2014 Pop III stars behind gravitational lenses \u2014 may not be as rare as previously feared.\u201d The researchers now plan to carry out detailed simulations of the transition between Pop III stars and the next generation (Pop II), to test whether the theoretical models match the signal observed in the spectrum of LAP1-B and other similar objects.<\/p>\n","protected":false},"excerpt":{"rendered":"The Webb telescope illuminates the cosmic dawn: possible traces of the first stars that formed in the very…\n","protected":false},"author":2,"featured_media":95747,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,39427,12406,56896,66,803,14311,831,16132],"class_list":["post-295683","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-cosmic","tag-dawn","tag-illuminates","tag-science","tag-stars","tag-telescope","tag-universe","tag-webb"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/295683","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=295683"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/295683\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/95747"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=295683"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=295683"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=295683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}