Direct Images Capture Aligned Protostellar Jets for the First Time
For the first time, direct images of aligned protostellar jets have been captured. This discovery supports the idea that stars, when forming from collapsing gas clouds, tend to rotate in the same direction.
Astronomers aimed the James Webb Space Telescope at the Serpens Nebula, located about 1,300 light-years from Earth. This nebula is one or two million years old, which is just a blink of an eye in cosmic terms. As the telescope observed this nebula, it revealed something extraordinary, finally confirming theories about star formation.
Serpens Nebula
Below is the new image of the stunning Serpens Nebula. This nebula hosts a remarkably dense cluster of newly formed stars (about 100,000 years old), visible in the center of the image. Some of these stars will eventually reach the same mass as our sun. “Webb is an incredible tool for spotting young stars,” says researcher Joel Green. “In this area, we found indications of every young star, even those with the smallest mass.”
In this image, the filaments and strands running throughout the region represent reflected light from protostars still forming within the nebula. Some areas show an orange, diffuse reflection due to dust scattering and reflecting the light. The photo was taken with the Near-Infrared Camera (NIRCam) of NASA’s James Webb Space Telescope. While it’s a beautiful picture, the real discovery lies in the northern area (visible in the upper left) of this young, nearby star formation region.
Aligned Jets
Astronomers discovered a fascinating group of protostellar jets here. These jets form when gas streams from newborn stars collide with surrounding gas and dust at high speed. Normally, these jets have various orientations within one region. But here, they are all tilted in the same direction, like hail during a storm. Researchers identified these aligned jets thanks to Webb’s exceptional spatial resolution and sensitivity in the near-infrared. This provides new insights into the fundamental principles of star formation.
Star Formation
The discovery of these aligned jets is significant. It confirms existing theories about how stars come into existence. “Astronomers have long believed that when gas clouds collapse to form stars, these stars usually rotate in the same direction,” explains researcher Klaus Pontoppidan. “However, this has not been directly observed before. These aligned, elongated structures provide evidence of the fundamental processes by which stars are born.”
Rotation
You might wonder how the alignment of gas and dust jets around the star correlates with its own rotation. When an interstellar gas cloud compresses to form a star, its rotational speed increases. Around the young star, a disk of material forms, working like a whirlpool drawing matter towards the center. The magnetic fields in this disk cause some of the material to be ejected in twin jets that move perpendicular to the disk in opposite directions. In the Webb image, these jets are shown as bright, lumpy streaks that appear red. This color indicates shockwaves created when the jets hit nearby gas and dust. The red color signifies the presence of molecular hydrogen and carbon monoxide in these areas.
Blurry Spots
We can observe this area of the Serpens Nebula so clearly now, thanks entirely to the powerful space telescope. “Thanks to Webb, we can now observe these very young stars and their jets,” Green emphasizes. “Previously, these objects were often only seen as blurry spots, or even completely invisible in optical wavelengths due to the dense dust surrounding them.”
Changing Directions
The discovery of aligned jets does not automatically mean they will always stay aligned. They can lose their alignment over time due to various factors, such as interaction with nearby stars or gravitational disturbances within their environment. An example is when binary stars orbit each other, which can lead to a change in the direction of the jets they produce. This means the alignment currently observed is not necessarily permanent and could change as conditions evolve.
Chemical Composition
The new, spectacular image and the unexpected discovery of the aligned jets are just the beginning. The team will now use Webb’s NIRSpec (Near-Infrared Spectrograph) to investigate the chemical composition of the cloud in detail. The astronomers aim to understand how volatile chemicals survive the formation of stars and planets. Volatile substances are compounds that sublimate, meaning they transition directly from a solid to a gas phase at relatively low temperatures – like water and carbon monoxide. The researchers will then compare their findings with the amounts found in protoplanetary disks around similar types of stars.
Why are researchers so interested in this? “We are essentially all made up of material stemming from these volatile substances,” Pontoppidan explains. “Most of the water here on Earth originated when our sun was still a young protostar, billions of years ago. By looking at the amount of these crucial compounds in protostars just before their protoplanetary disks formed, we can better understand how unique the conditions were when our own solar system formed.” The findings thus contribute to a better understanding of the conditions that led to the formation of our own solar system and highlight the ability of the Webb telescope to provide new and detailed insights into the birth of stars and planets.
