Using the James Webb Space Telescope, astronomers discovered that the Orion Nebula’s planet-forming disk actually surrounds a “failed star,” or brown dwarf. This is the first confirmation that flat clouds of gas and dust, called “protoplanetary disks” that form planets, surround these unusual cosmic objects.
The researchers discovered this while using the James Webb Space Telescope (JWST) to follow observations of protoplanetary disks, or “propulids,” illuminated by ultraviolet light in the Orion Nebula. These observations were collected by the Hubble Space Telescope.
These discoveries could help scientists understand how brown dwarfs form and why they fail to clear the final hurdle needed to become full-fledged stars. There is. Additionally, the discovery could help determine whether these free-floating objects could eventually have orbiting planets of their own, even if they fail to become proper stars.
Brown dwarfs have earned the somewhat unfair nickname of “failed stars” because they form directly from vast clouds of star-like gas and dust. But it is unable to muster enough mass to create the pressure and temperature within its core necessary to trigger the fusion of hydrogen into helium, the process that defines a star’s main sequence lifetime.
Brown dwarfs have masses between 13 and 75 times that of Jupiter, or 0.13 to 0.75 times that of the Sun, and cooler temperatures. Therefore, it emits weak, low-energy infrared radiation.
“Stars are born in cosmic giant clouds of gas and dust called nebulae, which are several light years in diameter,” said team co-leader Kevin Luhmann of Penn State’s Eberly College of Science. . said in a statement. “Astronomers have long believed for decades that planets do not form immediately after stars merge in nebulae, in a disk of gas and dust surrounding the newborn star, known as a protoplanetary disk. That’s what I was thinking.”
Brown dwarfs may not fail as planetary parents
Shortly after Hubble’s launch in 1990, NASA’s pioneering space telescope captured direct images of the protoplanetary disk of the Orion Nebula. Located just 1,500 light-years away, the constellation Orion is the closest large star-forming region to Earth and is home to about 2,000 newborn stars.
“Some objects born in nebulae, such as Orion, have too little mass to undergo hydrogen fusion, so they are cold and dark and do not qualify as full-fledged stars,” said Team Leader said Catalina Alves de Oliveira, one of them. said the European Space Agency’s (ESA) head of science operations and development in a statement. “These star-like objects without nuclear fusion are known as brown dwarfs. The question is: Can we find proprids around brown dwarfs in Orion?”
In fact, some of the proprid stars observed by Hubble in the Orion Nebula appeared to have faint objects at their centers, which may be brown dwarfs. But the problem is that the observations collected by Hubble weren’t sensitive enough to determine whether these faint objects have the lower temperatures associated with these failed stars.
That’s where JWST, the most sensitive infrared space telescope ever built by humanity, steps in. This is ideal for measuring the temperature of dark objects in the Orion Nebula, which may be brown dwarfs, including Proplids, which were observed by Hubble 30 years ago.
Astronomers performed spectroscopic measurements on several potential brown dwarf objects in the constellation Orion and found that at least 20 of them are cool enough to be named brown dwarfs. The smallest of these has about 0.05 times the mass of the Sun and about 5 times the mass of Jupiter.
The research team also discovered two objects that lie on the proposed boundaries of the mass needed to start a significant fusion reaction. These two have about 0.75 times the mass of the Sun. Therefore, the researchers were unable to deduce whether these two objects were large brown dwarfs or small stars.
“The new JWST observations only scratch the surface when it comes to Orion’s brown dwarfs,” Luhmann said. “This nebula contains hundreds of faint objects that may be brown dwarfs, and is ready for spectroscopy by JWST. Future observations of Orion by JWST will More examples of proprids may be discovered and the minimum mass of brown dwarfs could be determined.”
“This information helps fill gaps in our knowledge about how brown dwarfs form and their relationships with stars and planets.”
The team’s research has been accepted for publication in The Astrophysical Journal and preprints are available on the repository site arXiv.
