Planet-forming material has been discovered in a part of a nearby galaxy where planets were thought not to emerge. ) suggests that planet formation may be more common throughout the universe than previously thought.
“I’ve been waiting a long time to be able to make these observations,” says Olivia Jones, an astrophysicist at the British Center for Astronomical Technology in Edinburgh and lead author of the study. “I couldn’t before.”
The findings follow a slew of discoveries made possible by JWST, which began in December 2021 and sent its first scientific images last July.
The researchers focused on NGC 346, a very active star-forming region in a galaxy near the Milky Way called the Small Magellanic Cloud (SMC). They chose this location because it has very low concentrations of metals, which astronomers define as elements heavier than hydrogen and helium.
This is analogous to “cosmic noon,” when stars formed all at once in nearly every galaxy in the universe about 10 billion years ago. Moreover, NGC 346 is much larger than other nearby star-forming regions, allowing astronomers to see more clearly how stars interact and form.
Searching for low-mass stars
Researchers were primarily interested in studying low-mass stars. Because they are much more common in the universe than massive stars. Since the Sun is a low-mass star, understanding star formation in NGC 346 also helps explain the birth of the Solar System.
However, it has been difficult to study the birth of low-mass stars. Because they emit a lot of dust when they form, they mask the light. The best way to see through dust is to catch infrared light. This was not what JWST’s predecessor, the Hubble Space Telescope, was designed to do. “On the Web, you can see these stars at the moment they are born,” says Jones.
But dust is also important for detecting planet formation. The dust emitted when a star is born collects in a disk that eventually turns into a planet. It was not known if enough dust could survive on NGC 346 to form a planet. This is because low metal conditions make such disks susceptible to rapid evaporation by light.
impossible planet
The researchers used JWST’s camera’s filters to find a combination of infrared wavelengths that allowed them to identify stars in different stages of their lives. They found enough dust to show that planet formation is possible, and collected it in a characteristic way.
Stefanie Milam, deputy project scientist for JWST Planetary Science at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said that finding the components of NGC 346’s planets will help us understand where the planets might exist. said to broaden the understanding of “This gives us much more realm than was originally envisioned to begin exploring planet formation and star formation,” she said.
Researchers understand how rocky planets can collect more dust as they begin to form in low-metal galaxies, says Jones. Whether there is enough dust left to survive remains a mystery, she says.
what’s next?
It’s too early to tell whether the presence of more planets will increase the likelihood of life elsewhere in the universe, says Jones. I would like to look more closely at NGC 346 for signs of a particular substance in
Jones plans to use the JWST to make follow-up observations in about six months, targeting potential planetary systems reported in the latest study. Further in the future, investigating whether other unexpected galaxies can foster planet formation will help us better understand how the process works.
“I think the space of discovery is just endless,” says Milam. “Certainly, we are ready for the next generation of astrophysics.”
This article is reproduced with permission and was first published on April 24, 2023.
