This is an artist’s rendering of a young star surrounded by a disk of gas and dust. An international team of astronomers used NASA’s James Webb Space Telescope to study the disk around a young, very low-mass star known as ISO-ChaI 147. The results reveal the richest hydrocarbon chemistry yet observed in a protoplanetary disk. Credit: NASA/JPL-Caltech
Using The James Webb Space Telescopescientists have discovered a rich array of carbon molecules in the protoplanetary disk around a low-mass star, suggesting a unique type of planetary environment that could lead to the formation of carbon-poor planets.
An international team of astronomers studied the disk of gas and dust around a young, very low-mass star NASAThe James Webb Space Telescope (JWST). The results reveal the largest number of carbon-containing molecules ever observed in such a disk. These findings have implications for the potential composition of any planets that might form around this star.
Implications for planet formation
Rocky planets are more likely than gas giants to form around low-mass stars, making them the most common planets around the most common stars in our galaxy. Little is known about the chemistry of such worlds, which may be similar to or very different from Earth. By studying the disks from which such planets form, astronomers hope to better understand the process of planet formation and the composition of the resulting planets.
Planet-forming disks around very low-mass stars are difficult to study because they are smaller and fainter than disks around high-mass stars. The program, called the MIRI (Mid-Infrared Instrument) Mid-INfrared Disk Survey (MINDS), aims to use Webb’s unique capabilities to build a bridge between the chemical inventory of disks and the properties of exoplanets.
“Webb has better sensitivity and spectral resolution than previous infrared space telescopes,” explained project lead author Aditya Arabhavi of the University of Groningen in the Netherlands. “These observations are not possible from Earth because the emission from the disc is blocked by our atmosphere.”
The spectrum of star ISO-ChaI 147 revealed by NASA’s James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) shows the richest hydrocarbon chemistry yet observed in a protoplanetary disk, consisting of 13 carbon-bearing molecules. This includes the first extrasolar detection of ethane (C2H6). The team also successfully detected ethylene (C2H4), propyne (C3H4) and the methyl radical CH3 in the protoplanetary disk for the first time. Acknowledgments: NASA, ESA, CSA, R. Crawford (STScI)
Groundbreaking discoveries in exoplanetary chemistry
In the new study, the team examined the region around a very low-mass star known as ISO-ChaI 147, a 1- to 2-million-year-old star that weighs just 0.11 times that of the Sun. The spectrum revealed by Webb’s MIRI shows the richest hydrocarbon chemistry yet observed in a protoplanetary disk—a total of 13 different carbon-bearing molecules. The team’s findings include the first detection of ethane (C2H6) outside our solar system, as well as ethylene (C2H4), propine (C3H4) and the methyl residue CH3.
“These molecules have already been detected in our solar system, such as in comets like 67P/Churyumov–Gerasimenko and C/2014 Q2 (Lovejoy),” Arabhavi added. “Webb allowed us to understand that these hydrocarbon molecules are not only diverse but also abundant. It is amazing that we can now see the dance of these molecules in the planetary cradles. It’s a very different environment for planet formation than we usually imagine.”
The team suggests that these results have major implications for the chemistry of the inner disk and the planets that might form there. Because Webb revealed that the gas in the disk is so rich in carbon, there is probably little carbon left in the solid materials that would form the planets. As a result, the planets that could form there may end up being poor in carbon. (Earth itself is considered carbon-poor.)
“This is fundamentally different from the composition we see in disks around solar-type stars, where oxygen-carrying molecules such as water and carbon dioxide dominate,” added team member Inga Kamp, also from the University of Groningen. “This object demonstrates that this is a unique class of object.”
“It is incredible that we are able to detect and quantify the abundance of molecules we know well on Earth, such as benzene, in an object more than 600 light-years away,” added team member Agnés Perrin of the Center National de la Recherche Scientifique. in France.
Future research directions
Next, the science team intends to extend their study to a larger sample of such disks around very low-mass stars to understand how common or exotic such carbon-rich planet-forming terrestrial regions are. “Extending our study will also allow us to better understand how these molecules can form,” explained team member and MINDS principal investigator Thomas Henning of the Max-Planck-Institute for Astronomy in Germany. “Several features in the Webb data are also still unidentified, so more spectroscopy is needed to fully interpret our observations.”
This work also highlights the critical need for scientists to collaborate across disciplines. The team notes that these results and accompanying data may contribute to other fields including theoretical physics, chemistry and astrochemistry, to the interpretation of spectra and to the investigation of new properties in this wavelength range.
For more information on this discovery, see Webb unlocks the secrets of carbon-rich protoplanetary disks.
Reference: “Hydrocarbon value in the disk around a very low mass star” by AM Arabhavi, I. Kamp, Th. Henning, EF van Dishoeck, V. Christiaens, D. Gasman, A. Perrin, M. Güdel, B. Tabone, J. Kanwar, LBFM Waters, I. Pascucci, M. Samland, G. Perotti, G. Bettoni, SL Grant, PO Lagage, TP Ray, B. Vandenbussche, O. Absil, I. Argyriou, D. Barrado, A. Boccaletti, J. Bouwman, A. Caratti or Garatti, AM Glauser, F. Lahuis, M. Mueller, G Olofsson, E. Pantin, S. Scheithauer, M. Morales-Calderón, R. Franceschi, H. Jang, N. Pawellek, D. Rodgers-Lee, J. Schreiber, K. Schwarz, M. Temmink, M. Vlasblom. , G. Wright, L. Colina, and G. Östlin, 6 Jun 2024, Science.
DOI: 10.1126/science.adi8147
The James Webb Space Telescope is the world’s leading observatory for space science. Webb solves mysteries in our solar system, looks further to distant worlds around other stars, and explores the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners ESA (European Space Agency) and CSA (Canadian Space Agency).