NASA’s Webb Telescope Discovers Record-Breaking Carbon Molecules Around Young Star

An international team of astronomers used NASA’s James Webb Space Telescope to study the disk of gas and dust around a young, low-mass star, revealing the largest number of carbon-containing molecules seen to date in such a disk. The star, known as ISO-ChaI 147, is surrounded by a disk rich in hydrocarbon chemistry, including the first detection of ethane outside of our solar system. The findings, led by Aditya Arabhavi of the University of Groningen, suggest that planets forming around this star may be carbon-poor. The team plans to expand their study to understand how common such carbon-rich regions are.

Unprecedented Carbon Molecule Discovery Around Young Star

An international team of astronomers has utilized NASA’s James Webb Space Telescope to examine the disk of gas and dust surrounding a young, very low-mass star. The results of this study have revealed the most significant number of carbon-containing molecules ever observed in such a disk. This discovery has potential implications for the composition of any planets that may form around this star.

Low-mass stars are more likely to form rocky planets than gas giants, making them the most common planets around the most common stars in our galaxy. However, the chemistry of these worlds remains largely unknown and could be similar to or vastly different from Earth. By studying the disks from which these planets form, astronomers hope to gain a better understanding of the planet formation process and the compositions of the resulting planets.

The Challenges and Solutions in Studying Low-Mass Stars

Studying planet-forming disks around very low-mass stars presents a challenge due to their smaller and fainter nature compared to disks around high-mass stars. To bridge the gap between the chemical inventory of disks and the properties of exoplanets, a program called the MIRI (Mid-Infrared Instrument) Mid-INfrared Disk Survey (MINDS) aims to utilize Webb’s unique capabilities.

Webb’s superior sensitivity and spectral resolution compared to previous infrared space telescopes have made these observations possible. The emissions from the disk, which are blocked by our atmosphere, can now be studied in detail.

The Rich Hydrocarbon Chemistry of ISO-ChaI 147

The team focused their study on 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 as much as the Sun. The spectrum revealed by Webb’s MIRI shows the richest hydrocarbon chemistry seen to date in a protoplanetary disk – a total of 13 different carbon-bearing molecules. This includes the first detection of ethane (C2H6) outside of our solar system, as well as ethylene (C2H4), propyne (C3H4), and the methyl radical CH3.

These molecules have previously been detected in our solar system, like in comets such as 67P/Churyumov–Gerasimenko and C/2014 Q2 (Lovejoy). Webb’s observations have shown that these hydrocarbon molecules are not just diverse but also abundant in the planetary cradles.

Implications for Planet Formation and Composition

The team’s findings suggest that these results have significant implications for the chemistry of the inner disk and the planets that might form there. Since Webb revealed the gas in the disk is so rich in carbon, there is likely little carbon left in the solid materials that planets would form from. As a result, the planets that might form there may ultimately be carbon-poor, similar to Earth.

This is profoundly different from the composition seen in disks around solar-type stars, where oxygen-bearing molecules like water and carbon dioxide dominate. This object establishes that these are a unique class of objects.

Future Studies and Interdisciplinary Collaboration

The science team plans to extend their study to a larger sample of such disks around very low-mass stars to develop their understanding of how common or exotic such carbon-rich terrestrial planet-forming regions are. The expansion of the study will also allow them to better understand how these molecules can form. Several features in the Webb data are still unidentified, so more spectroscopy is required to fully interpret the observations.

This work also underscores the crucial need for scientists to collaborate across disciplines. The team notes that these results and the accompanying data can contribute towards other fields including theoretical physics, chemistry, and astrochemistry, to interpret the spectra and to investigate new features in this wavelength range.