detected carbon monoxide and carbon dioxide ice on trans-Neptunian objects (TNOs) for the first time<\/a> earlier this year.<\/p>\nThose observations, paired with ones of Chiron, are creating foundational knowledge for understanding the creation of our Solar System, as these objects have largely remained unchanged since the Solar System was formed, Pinilla-Alonso says.<\/p>\n
\u201cAll the small bodies in the Solar System talk to us about how it was back in time, which is a period of time we can\u2019t really observe anymore,\u201d she says. \u201cBut active centaurs tell us much more. They are undergoing transformation driven by solar heating and they provide a unique opportunity to learn about the surface and subsurface layers.\u201d<\/p>\n
Since Chiron possesses characteristics of both an asteroid and a comet, it makes it rich for studying many processes that could assist in understanding them, she says.<\/p>\n
\u201cWhat is unique about Chiron is that we can observe both the surface, where most of the ices can be found, and the coma, where we see gases that are originating from the surface or just below it,\u201d Pinilla-Alonso says. \u201cTNOs don\u2019t have this kind of activity because they\u2019re too far and too cold. Asteroids don\u2019t have this kind of activity because they don\u2019t have ice on them. Comets, on the other hand, show activity like centaurs, but they are typically observed closer to the sun, and their comas are so thick that they complicate the interpretations of observations of the ices on the surface. Discovering which gases are part of the coma and their different relationships with the ices on the surface help us learn the physical and chemical properties, such as the thickness and the porosity of the ice layer, its composition, and how irradiation is affecting it.\u201d<\/p>\n2060 Chiron Chemical Composition. The colored bands highlight the different ices such as water ice, carbon oxides and light hydrocarbons. Inset: Detail of 2060 Chiron reflectance highlighting the fluorescence of methane gas together with absorptions of ethane and propane ices. (Image credit: William Gonzalez Sierra)<\/figcaption><\/figure>\nThe discovery of these ices and gases on an object as distant as Chiron \u2013 observed near its farthest point from the sun \u2013 is exciting because it could help contextualize other centaurs and provide insight into the earliest era of our Solar System, Schambeau says.<\/p>\n
\u201cThese results are like nothing we\u2019ve seen before,\u201d he says. \u201cDetecting gas comae around objects as far away from the sun as Chiron is very challenging, but JWST has made it accessible. These detections enhance our understanding of Chiron\u2019s interior composition and how that material produces the unique behaviors as we observe Chiron.\u201d<\/p>\n
Schambeau specializes in studying centaurs, comets and other space objects. He analyzed the methane gas coma and determined that the outflowing gas detected was consistent with it being sourced from a surface area that was exposed to the most heating from the sun.<\/p>\n
Chiron, first discovered in 1977, is characterized much better than most centaurs and comparatively is unique, Schambeau says. The newly analyzed information helps scientists better understand the thermophysical process going on in Chiron that produces methane gas, he says.<\/p>\n
\u201cIt\u2019s an oddball when compared to the majority of other Centaurs,\u201d Schambeau says. \u201cIt has periods where it behaves like a comet, it has rings of material around it, and potentially a debris field of small dust or rocky material orbiting around it. So, many questions arise about Chiron\u2019s properties that allow these unique behaviors.\u201d<\/p>\nAn artistic representation of Chiron’s nucleus surrounded by debris and a coma of dust and gas. (Image credit: William Gonzalez Sierra)<\/figcaption><\/figure>\nThe researchers concluded that the coexistence of the molecules in various states adds another layer of intrigue for studying comets and centaurs. The study also highlighted the presence of irradiated byproducts of methane, carbon monoxide and carbon dioxide that will require further research and could help scientists further reveal the unique processes producing Chiron\u2019s surface composition.<\/p>\n
Chiron originated from the TNO region and has traveled around our Solar System since its creation, says Pinilla-Alonso. The orbits of Chiron and many other large non-planetary objects occasionally experience close encounters with one of the giant planets where the gravitational pull from the planet changes the smaller object\u2019s orbit, taking them all over our Solar System and exposing them to many different environments, she says.<\/p>\n
\u201cWe know it has been ejected from the TNO population and is only now transiting through the region of the giant planets, where it will not stay for too long,\u201d Pinilla-Alonso says. \u201cAfter about 1 million years, centaurs like Chiron typically are ejected from the giant planets region, where they may end their lives as Jupiter Family comets or they may return to the TNOs region.\u201d<\/p>\n
Pinilla-Alonso notes that the JWST\u2019s spectra showed for the first time Chiron\u2019s plethora of ices with different volatilities and their formation processes, she says.<\/p>\n
Some of these ices, such as methane, carbon dioxide, and water ice, may be primordial components of Chiron inherited from the pre-solar nebula. Others, such as acetylene, propane, ethane, and carbon oxide, could have formed on the surface because of reduction and oxidation processes, she says.<\/p>\n
\u201cBased on our new JWST data, I\u2019m not so sure we have a standard centaur,\u201d Pinilla-Alonso says. \u201cEvery active centaur that we are observing with JWST shows some peculiarity. But they cannot be all outliers. There must be something that explains why they appear to all behave differently or something that is common between them all that we cannot yet see.\u201d<\/p>\n
![\"2060](\"https:\/\/www.ucf.edu\/wp-content\/blogs.dir\/20\/files\/2024\/12\/Chiron-graphs.jpg\")
![\"An](\"https:\/\/www.ucf.edu\/wp-content\/blogs.dir\/20\/files\/2024\/12\/02-Chiron-Traveling-with-debris-300x180.jpg\")