Was planetary formation different during the early universe than today? This is what a recent study published in The Astrophysical Journal hopes to address as an international team of researchers investigated whether planets could form with a lack of heavy elements, building off a 2003 finding from NASA’s Hubble Space Telescope, which identified a 13-billion-year-old planet, almost as old as the universe. Therefore, with a planet that old, could this mean that other planets could have formed in the early universe with protoplanetary disks that had a far lesser number of heavy elements than our solar system had when it formed?
“The Hubble findings were controversial, going against not only empirical evidence in our galaxy but also against the current models,” said Dr. Guido De Marchi, who is an astronomer at the European Space Research and Technology Centre and lead author of the study. “This was intriguing, but without a way to obtain spectra of those stars, we could not really establish whether we were witnessing genuine accretion and the presence of disks, or just some artificial effects.”
For this new study, astronomers used NASA’s powerful James Webb Space Telescope (JWST) to verify Hubble’s 20-year-old findings with the goal of better understanding if conditions in the early universe could result in planetary formation. Using JWST’s powerful spectroscopy instruments, the researchers observed stars forming within NGC 346, which is a star-forming cluster in the Small Magellanic Cloud located approximately 210,000 light-years from Earth. In the end, the researchers discovered that despite the decreased number of heavy elements in these disks, planets could still form if given enough time.
Image of NGC 346 obtained by NASA’s James Webb Space Telescope with yellow circles depicting the stars examined for this study. (Credit: NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA))
“We see that these stars are indeed surrounded by disks and are still in the process of gobbling material, even at the relatively old age of 20 or 30 million years,” said Dr. De Marchi. “This also implies that planets have more time to form and grow around these stars than in nearby star-forming regions in our own galaxy.”
These findings could challenge longstanding hypotheses that star-forming disks in the early universe weren’t able to form planets due to the lack of heavy elements, but now astronomers could consider the possibility that planets existed in the early universe.
What new discoveries about planets forming in the early universe will astronomers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: The Astrophysical Journal, NASA, EurekAlert!, NASA (1)