Webb Telescope Reveals Parallel Jets from Baby Stars

The latest image taken by the James Webb Space Telescope does not disappoint. A spectacular vista of the Serpens Nebula, captured by the telescope’s near-infrared camera, reveals a never-before-seen feature of early star formation.

The telescope has detected unprecedented details in young stars’ gaseous outflows, which form as the newborn stars gather material around them. The jets of gas collide with gas and dust from the nebula itself, and their detection could shed valuable insight into the birth of stars.

The discovery can be found in the top left corner of the image, where a torrent of neatly aligned red and orange streaks — signifying molecular hydrogen and carbon monoxide — looms over the nebula’s bluish clouds of reflected starlight at image center. With Webb’s clearer picture of this stellar nursery, astronomers hope to learn more about how young stars form and evolve together in a nebulous environment.

A Star Is Born

Those streaks are protostellar outflows, a natural product of star formation. As pockets within a nebula begin to collapse into rotating balls of gas, their spin will increase as angular momentum is conserved — the principle is the same as for figure skaters, who spin faster as they draw their arms inward. In order for the gas to actually fall onto the newborn star, some of this angular momentum must be lost through jets of gas, which are funneled from the star’s poles at incredible speeds of tens of kilometers per second.

These spurts of energy from embryonic stars become visible as shockwaves of ionized, molecular, and atomic gas collide with nearby material. Such protostellar outflows have been seen before — what’s unique about this detection is their near-perfect alignment.

“The special significance of the result is that almost all outflows are pointed in the same direction to within +/-10 degrees, which is extremely unlikely to happen by chance,” says Joel Green (Space Telescope Science Institute), who led the study to appear in the Astrophysical Journal. “This means that stars are forming together as they fragment out of a larger collapsing cloud, like a litter of kittens, rather than one at a time.”

In the study, Green and colleagues identified 12 pairs of jets in the northwest region that are all aligned with the Serpens filament, a section of the nebula that’s a hotbed for star formation. These findings confirm that baby stars form in clusters, born from the collapse of molecular clouds.

“Although theory has long predicted that stars form in such groups, this clustered and aligned spin has not been seen so clearly before and is a powerful confirmation of our understanding of how stars like the Sun form,” Green said.

Webb’s sensitivity at mid-infrared wavelengths allowed it to more clearly detect the jet’s signposts — molecular hydrogen, carbon monoxide, and ionized iron  — than its predecessors such as the Spitzer Space Telescope. And the telescope’s higher resolution caught the outflows’ alignment for the first time.

Stellar Laboratories

The Serpens Nebula is already an incredibly dense region of star formation, containing about 100,000 stars but spanning only a few light-years. It would fit entirely between the Sun and our closest neighbor Proxima Centauri. The outflows are between 200 and 1,400 years old, and the entire nebula is only 1 to 2 million years old.

“We hope to learn whether star formation is usually guided by the collapse of filamentary clouds like Serpens,” Green says. This stellar nursery will eventually produce stars like our own, and surveying the Serpens region may clarify what such collapse really looks like. Our Sun probably formed from a cloud much larger than Serpens, so astronomers are eager to investigate other star-forming regions for comparison.

Only 1,300 light-years from Earth, the Serpens Nebula is a captivating interstellar laboratory for astronomers. Besides the protostellar outflows, the nebula is also home to several disk shadows — shadows cast by whirling disks of gas and dust that form around young stars and set the stage for planet formation. One of these disk shadows — dubbed the “Bat Shadow” when it was detected by Hubble in 2018  — is visible at the center of the image. Probing the region’s chemical composition could also shed light on the chemistry that drives protostars to coalesce and form planets.

With the aid of the Webb telescope, astronomers are capturing the extraordinary moments of protostellar creation in order to better understand how a star is born.