Remarkable new web image showing alignment of dipole jets confirms star formation theories

For the first time, a phenomenon that astronomers had long hoped to image directly has been captured by the James Webb Space Telescope’s (NASA/ESA/CSA) Near Infrared Camera (NIRCam). In this stunning image of the Serpens Nebula, the discovery is made in the northern region of this young region close to the star.

Astronomers have found an interesting group of protostellar streams that form when gas jets from newborn stars collide with nearby gas and dust at high speeds. Typically, these objects have different orientations in the same area. Here, however, they are all slanted in the same direction, to the same degree, like rain falling during a storm.

The discovery of these aligned objects, made possible only by the Web’s extraordinary spatial resolution and sensitivity at near-infrared wavelengths, provides insights into the fundamentals of how stars are born.

So how does the arrangement of stellar jets relate to the star’s rotation? As an interstellar gas cloud collapses in on itself to form a star, it spins faster. The only way for the gas to continue moving inward is to remove some of the spin (aka angular momentum).

A disk of material forms around the young star to transport material downward, like an eddy around a drain. Rotating magnetic fields in the inner disk throw some of the material into the twin jets, which shoot material outward in opposite directions perpendicular to the disk.

In the web image, these jets are identified by bright red mass streaks, which are shock waves created when the jet collides with the surrounding gas and dust. Here the red color indicates the presence of molecular hydrogen and carbon monoxide. Webb can image these very young stars and their outflows that were previously blocked at wavelengths of light.

Astronomers say there are few forces that could potentially change the direction of the outflow during this period of a young star’s life. One way is that binary stars orbit each other and rotate in their direction, twisting the direction of the outflow over time.

The stars of the Serpent Nebula

The Serpentine Nebula is only one or two million years old, which is very young in cosmic terms. It is also home to a dense cluster of newly formed stars (about 100,000 years old) at the center of this image, some of which will eventually reach the mass of our Sun.

The Serpent is a reflection nebula, meaning it is a cloud of gas and dust that does not produce its own light, but shines by reflecting light from nearby stars or within the nebula.

Thus, across the region in this image, the various filaments and colors represent starlight reflected from the forming protostars in the cloud. In some areas of the dust there is a reflection against it, which here appears orange and diffuse.

The region has been home to other serendipitous discoveries, including the “Bat Shadow,” which got its name when 2020 data from the NASA/ESA Hubble Space Telescope showed it moving. This feature can be seen in the center of Webb’s image.

Future studies

The stunning image and surprising discovery of aligned objects is actually the first step in this scientific program. The team will now use Webb’s NIRSpec (Near Infrared Spectrophotometer) to investigate the chemical composition of the cloud.

Astronomers are interested in determining how volatile chemicals survive star and planet formation. Volatile substances are compounds that sublime at relatively low temperatures—including water and carbon monoxide—or change directly from a solid to a gas. They then compare their findings with values ​​found in the protoplanetary disks of similar stars.

These observations were made as part of the Webb General Observer 1611 program (PI: K. Pontoppidan). The preliminary results of this team have been published on the site Journal of Astrophysics.