Very low-mass stars orbit rocky exoplanets more frequently than other types of stars. The composition of these planets is poorly understood, but it is thought to be related to the protoplanetary disk in which they form. In the new study, astronomers used the NASA/ESA/CSA James Webb Space Telescope to investigate the chemical composition of the planet-forming disk around ISO-ChaI 147, a red dwarf star just one-tenth the mass of the Sun. They identified emission from 13 carbon-containing molecules, including ethane and benzene.
This is an artist's impression of a young star surrounded by a disk of gas and dust. Image courtesy of NASA/JPL.
ISO-ChaI 147 It is a red dwarf star with a mass 0.11 times that of the Sun, located about 639 light years away in the constellation Chamaeleon.
The star was observed as part of the MIRI Mid-Infrared Disk Survey (MINDS), which aims to bridge the gap between the chemical composition of the disk and the properties of exoplanets.
These observations provide insight into the environments and fundamental elements for the formation of such planets.
Astronomers discovered that the gas in ISO-ChaI 147's planet-forming region is rich in carbon.
This could be due to carbon being removed from the solid material from which rocky planets form, which could explain why Earth is relatively carbon-poor.
“WEBB has greater sensitivity and spectral resolution than conventional infrared space telescopes,” said Dr Aditya Arabavi, an astronomer at the University of Groningen.
“These observations are not possible from Earth because the radiation is blocked by the atmosphere.”
“So far we have only been able to identify acetylene emissions from this object.”
“But Webb's high sensitivity and spectral resolution allowed us to detect faint emissions from fewer molecules.”
“Thanks to Webb, we now know that these hydrocarbon molecules are not only diverse, but abundant as well.”
The spectrum of ISO-ChaI 147 shows the richest hydrocarbon chemical composition ever observed in a protoplanetary disk, consisting of 13 carbon-containing molecules. Image credit: NASA/ESA/CSA/Ralf Crawford, STScI.
The spectrum of ISO-ChaI 147 is Webb's mid-infrared measuring instrument (MIRI) displays the richest hydrocarbon chemical composition ever observed in a protoplanetary disk, consisting of 13 carbon-containing molecules up to benzene.
This includes the first extrasolar detection of ethane, the largest fully saturated hydrocarbon detected outside the solar system.
Fully saturated hydrocarbons are expected to form from more basic molecules, so detecting them here can give researchers clues about their chemical environment.
Astronomers also detected ethylene, propyne, and methyl radicals in a protoplanetary disk for the first time.
“These molecules have already been detected in our solar system, for example in comets such as 67P/Churyumov-Gerasimenko and C/2014 Q2 (Lovejoy),” Dr. Arababi said.
“It's amazing that we can now see these molecules dancing in the cradle of the planet.”
“This is a completely different environment to how we normally think of planet formation.”
The team note that these results have significant implications for the astrochemistry within 0.1 AU and the planets that form there.
“This is very different to the composition found in disks around solar-type stars, where oxygen-containing molecules (such as carbon dioxide and water) dominate,” said Dr Inga Kamp, also from the University of Groningen.
“This object proves that these are unique classes of objects.”
“It's incredible that we can detect and quantify the amount of a molecule that's well known on Earth, such as benzene, in an object more than 600 light years away,” said Dr Agnes Perrin, an astronomer at the French National Center for Scientific Research.
Team result Published in today's journal Science.
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AM Arabavi other2024. Abundant hydrocarbons present in a disk around a very low-mass star. Science 384, 6700: 1086-1090; doi: 10.1126/science.adi8147
Source: www.sci.news
