Webb captures commotion from nebula’s stellar jets

NASA/ESA/CSA's James Webb Space Telescope unveiled numerous stars formerly hidden by clouds of dust in the stellar nursery NGC 7129, a cosmic creation region 3,300 light-years from Earth. Webb observed infrared light, which pierces dense matter that scatters or absorbs other wavelengths. The region contains stellar objects at different stages of life and offers a chance to explore how stars shape their surroundings, with more massive stars forming and evolving fastest. The most massive and mature object is the luminous central star LkH(alpha) 234, which has the image's most prominent diffraction pattern and weighs about 5 to 8 times our Sun. Pre-main-sequence stars like this have mostly finished gathering mass and begun contracting under gravity, raising their temperatures; in time, the central star will fuse hydrogen like our Sun.

To the left of the central star, a gold-colored cavity spanning about 3.5 light-years is the largest demonstration of the star's impact. Outflows from an earlier stage of its life cycle carved into the dense molecular cloud of hydrogen. Both the outflows and the star's light energize the gas, causing it to glow. While much of this hydrogen is blown away, a large amount is compressed, creating conditions for more stars to form. A few of these young stars are visible within the cavity; several are also pre-main-sequence and generate stellar winds. Nearby bow shocks—curved compressed gas near the stars—form as those winds push into the energetic gas and create smaller cavities.

Together, the central star and embedded stars create a hot environment that pushes against colder, denser molecular gas, forming a boundary called a photodissociation region. In this region, hydrogen molecules break down into atoms. By influencing the heating, cooling, and chemistry of the area, this collection of stars offers insight into how these molecular clouds will gradually erode over millions of years.

The region to the right of the central star tells a different but equally chaotic story. Clumpy matter shown in red hides younger objects: protostars. The protostar stage is earlier than the pre-main-sequence stage and occurs after molecular clouds of gas and dust initially compress and fragment. As protostars accumulate matter and increase their mass, they eject outflows of superheated material. These outflows interact with the dense gray matter wrapping the protostars, creating shocks that give the region a textured appearance. The red glow also results from that interaction, similar to the outflows from the central pre-main-sequence star in the golden cavity. The excerpt notes multiple outflows from multiple stars in this region.