{"id":235656,"date":"2026-01-13T13:29:23","date_gmt":"2026-01-13T13:29:23","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/235656\/"},"modified":"2026-01-13T13:29:23","modified_gmt":"2026-01-13T13:29:23","slug":"most-planets-in-our-galaxy-are-born-bloated-new-study-suggests","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/235656\/","title":{"rendered":"Most planets in our galaxy are born \u2018bloated\u2019, new study suggests"},"content":{"rendered":"

Astronomers may have uncovered how the most common types of planets in our Galaxy<\/a> grow, a new study has revealed. The discovery confirms astronomers\u2019 theories that these planets start as ‘bloated’ babies but quickly lose much of their thick atmospheres.<\/p>\n

The study, published in Nature<\/a>, looked at four infant exoplanets<\/a> in the V1298 Tau system. Their star is just 20 million years old, making it the cosmic equivalent of a 5-month-old baby.<\/p>\n

Currently, the planets are five to 10 times the radius of Earth but have just five to 15 times its mass \u2013 giving them a similar density to polystyrene foam.<\/p>\n

This means the planets are \u2018puffed up\u2019, as the heat and light<\/a> of their young star is causing their atmospheres to expand enormously. The result is that the planets lose huge amounts of gas into space, meaning they will eventually contract and end up somewhere between Earth and Neptune in size.<\/p>\n

Though planets this size \u2013 also known as super-Earths and sub-Neptunes \u2013 have been found around many other stars, and are the most common variety we currently know of, one place you won\u2019t find them is in our own Solar System. <\/p>\n

Without an example of one of these intermediate worlds to study up close, they have been something of a \u2018missing link\u2019 in our understanding of how planets grow and form. \u00a0<\/p>\n

\u201cV1298 Tau is a critical link between the star- and planet-forming nebulae we see all over the sky, and the mature planetary systems that we have now discovered by the thousands,\u201d said Prof Erik Petigura<\/a> from the University of California, who took part in the study.<\/p>\n

Astronomers had previously theorised that infant planets grew in this way, as they had noticed many young planets were quite large, but this is the first time they have managed to catch the act as it was happening.<\/p>\n

\u201cThese planets have already undergone a dramatic transformation, rapidly losing much of their original atmospheres and cooled faster than what we\u2019d expect from standard models,\u201d said Prof James Owen<\/a>, a co-author from Imperial College London.<\/p>\n

\u201cBut they\u2019re still evolving. Over the next few billion years, they will continue to lose their atmosphere and shrink significantly, transforming into the compact systems of super-Earths and sub-Neptunes we see throughout the galaxy.\u201d<\/p>\n

A hole in one<\/p>\n

Like so many astronomical discoveries, the find relied as much on good luck as hard work and perseverance.<\/p>\n

The team were only able to examine the planets by looking at their transits \u2013 the brief dips in their star\u2019s brightness caused when the planet passed in front. The size of the dip can reveal information about a planet\u2019s radius, while the timing exposes the details of its orbit.<\/p>\n

\"StarPlanets only block out a tiny fraction of the star’s light, usually around 1 per cent, so it takes a lot of effort to pick them out. – Credit: ESA<\/p>\n

While the scientists knew the planets were on the larger side, some of the transits for the outer two planets had been missed, leaving a large question mark over their orbits.<\/p>\n

\u201cThere were hundreds of possibilities which we whittled down by running computer models and making educated guesses,\u201d said Petigura.<\/p>\n

They guessed well, it seemed, as when they went to look for the planet again with ground-based telescopes, they found it on the first try.<\/p>\n

\u201cI couldn\u2019t believe it,\u201d said Petigura. \u201cThe timing was so uncertain that I thought we would have to try half a dozen times at least. It was like getting a hole-in-one in golf.\u201d<\/p>\n

With all four orbits pinned down, the team could then do a much closer analysis to work out the planet\u2019s masses.<\/p>\n

As the planets pass each other, their gravity<\/a> pushes and pulls their orbits, subtly changing the timing of their transits. The bigger the mass of the planet, the bigger the pull, meaning the team were able to pick apart the timings of the transits to reveal the masses of the planets.<\/p>\n

\u201cThe unusually large radii of young planets led to the hypothesis that they have very low densities, but this had never been measured,\u201d said Trevor David from the Flatiron Institute<\/a>, who led the initial discovery<\/a> of the system in 2019.<\/p>\n

\u201cBy weighing these planets for the first time, we have provided the first observational proof. They are indeed exceptionally \u2018puffy,\u2019 which gives us a crucial, long-awaited benchmark for theories of planet evolution.\u201d<\/p>\n

Read more:<\/p>\n","protected":false},"excerpt":{"rendered":"Astronomers may have uncovered how the most common types of planets in our Galaxy grow, a new study…\n","protected":false},"author":2,"featured_media":235657,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[85,46,141,145],"class_list":["post-235656","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-il","tag-israel","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/235656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=235656"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/235656\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/235657"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=235656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=235656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=235656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}