{"id":10601,"date":"2025-09-11T23:44:08","date_gmt":"2025-09-11T23:44:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/10601\/"},"modified":"2025-09-11T23:44:08","modified_gmt":"2025-09-11T23:44:08","slug":"mysterious-soot-planets-may-be-hiding-in-plain-sight-among-the-stars","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/10601\/","title":{"rendered":"Mysterious \u201cSoot Planets\u201d May Be Hiding in Plain Sight Among the Stars"},"content":{"rendered":"

\t\t\"Artist\u2019s<\/a>Artist\u2019s depiction of a \u201csoot planet\u201d and its formation process. Credit: Ari Gea\/SayoStudio<\/p>\n

Some planets may be soot-rich rather than water-based. Atmosphere studies will be key to understanding their true nature.<\/p>\n

Astronomers generally consider water worlds to be among the most common types of planets in our galaxy, largely because of their low densities and the abundance of water ice beyond a star\u2019s \u201csnow line.\u201d However, a new study led by Jie Li and colleagues at the University of Michigan proposes an alternative explanation: some of these planets may not be dominated by water at all, but instead by a very different material known as soot.<\/p>\n

In astronomy, a soot planet is not literally a planet made of black powder. Here, \u201csoot\u201d refers to refractory organic carbon, a compound containing carbon, hydrogen, oxygen, and nitrogen that scientists often abbreviate as CHON. This type of carbon-rich material is widespread in the solar system, with estimates suggesting it accounts for as much as 40 percent of the total mass of comets.<\/p>\n

From comets to soot lines in planet formation<\/p>\n

Because comets are often considered snapshots of the solar system\u2019s early history, particularly during its protoplanetary phase, their composition suggests that soot was plentiful during the time planets were forming. The researchers propose that, just as there is a \u201csnow line\u201d marking the distance from a star where water ice can remain stable, there may also be a \u201csoot line.\u201d This boundary, located closer to the star than the snow line, would define the region where soot could persist and contribute significantly to the makeup of developing planets.<\/p>\n

Fraser discusses Water Worlds and how life might form on them.<\/p>\n

In fact, according to the paper, there would be three distinct zones of protoplanetary discs, each giving birth to a unique type of planet. The inner zone would only result in rocky works, like Earth and Mars, and it would be too hot for the soot to stay together, making \u201csoot\u201d in this area very unlikely. Past the \u201csoot line\u201d but before the \u201csnow line\u201d, planets could form that were mainly composed of soot, but with very little water, as it would still be too hot for water ice to exist in this area.<\/p>\n

These planets would look a lot like Titan, with methane atmospheres or something equivalent, and could be made up of as much as 25% soot by mass. Farther out past the \u201csnow line\u201d, most planets would be a combination \u201csoot-water world\u201d, where soot would still play a large role in the composition of the planet, but water would as well. In fact, the paper models two different types of soot-water worlds, a \u201cdry\u201d version that was only 25% water, and a \u201cwet\u201d one that contains 50% water, both of which would still contain 15-20% soot in their compositions.<\/p>\n

The problem of distinguishing planet types<\/p>\n

Those models show a particularly interesting feature \u2013 based on the mass-radius relationships, it is impossible to tell apart soot worlds and more traditional water worlds. In other words, many of the \u201cmini-Neptunes\u201d in the exoplanet catalog that were originally thought to be water worlds could actually be composed of carbon-rich materials rather than water. It would take looking at their actual atmospheres to determine which category they belonged to.<\/p>\n

Fraser discusses the discovery of methane, thought to be one of the main components of Soot Worlds, on exoplanet WASP-80b.<\/p>\n

The James Webb Space Telescope has already started doing so for some exoplanets. It\u2019s detected methane and carbon dioxide in the atmosphere of K2-12b and TOI-280d, two \u201csub-Neptunes\u201d that, while they are currently located within the soot line for their respective stars, might have formed outside of it and migrated inward over their lifetimes.<\/p>\n

In particular, TOI-280d has a notably high carbon to oxygen ratio, indicating that it might be a soot planet as described in the paper. These types of planets have interesting implications for habitability. They could have diamond cores, which would slow the cycling of volatiles in the planet\u2019s mantle and have a much harder time providing a magnetic field to protect any primitive life from cosmic rays. However, they would also be flush with methane and other volatile organics, which are thought to be prerequisites for prebiotic chemistry.<\/p>\n

Ultimately, understanding the fate of many of these planets will require \u2013 you guessed it \u2013 more data. Atmospheric checks, as well as more detailed models of ways to differentiate between water worlds and soot world,s need to be explored and delineated. While astronomers get to work on doing that, maybe an enterprising film director can pitch a movie about a character sailing an exoplanet\u2019s methane seas in an insulated boat. Kevin Costner\u2019s still actively acting after all.<\/p>\n

Reference: \u201cSoot Planets instead of Water Worlds\u201d by Jie Li, Edwin A. Bergin, Marc M. Hirschmann, Geoffrey A. Blake, Fred J. Ciesla and Eliza M.-R. Kempton, 22 August 2025, arXiv.
DOI: 10.48550\/arXiv.2508.16781<\/a><\/p>\n

Adapted from an article originally published on Universe Today<\/a>.<\/p>\n

Never miss a breakthrough: Join the SciTechDaily newsletter.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Artist\u2019s depiction of a \u201csoot planet\u201d and its formation process. Credit: Ari Gea\/SayoStudio Some planets may be soot-rich…\n","protected":false},"author":2,"featured_media":10602,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[1409,1410,9794,85,46,2760,9796,141],"class_list":{"0":"post-10601","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-astronomy","9":"tag-astrophysics","10":"tag-exoplanet","11":"tag-il","12":"tag-israel","13":"tag-planet-formation","14":"tag-planetary-science","15":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/10601","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=10601"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/10601\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/10602"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=10601"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=10601"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=10601"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}