NASA/ESA/CSA James Webb Space Telescope has unveiled numerous stars formerly hidden by clouds of dust in a stellar nursery known as NGC 7129 – a cauldron of cosmic creation, 3300 light-years from Earth. Webb captured infrared light, which pierces through the dense matter that scatters or absorbs other types of light. This region, rife with stellar objects in different stages of their lives, offers an opportunity to explore how stars shape their surroundings.
The stars from this cluster are in different stages of their development, as the more massive stars form and evolve the fastest. The most massive (and the most mature) is the region’s luminous central star, LkH(alpha) 234. This star, which sports the image’s most prominent diffraction pattern weighs around 5 to 8 times our Sun. So-called pre-main-sequence stars like these have mostly finished gathering mass and have begun contracting under the force of gravity, causing their temperatures to rise. In time, this star will fuse its own hydrogen like our Sun.
The cavity to its left, which appears in gold and spans about 3.5 light-years, is the largest demonstration of the central star’s impact. Outflows from an earlier stage of the star’s life cycle carve into the dense molecular cloud of hydrogen. Both the outflows and the star’s light energise the gas, causing it to glow. While much of this hydrogen gas is blown away, a large amount is also compressed, creating the conditions for even more stars to form.
A few of these young stars are visible within the cavity. Several of these are also pre-main-sequence and generate stellar winds. The nearby bow shocks, the curved compressed gas that appears near the stars, are created as those winds push into the energetic gas and form their own, smaller cavities.
Together, the central star and the embedded stars create a hot environment that pushes against the colder and denser molecular gas, and form a boundary known as a photodissociation region. In this region, the molecules of hydrogen break down into atoms. By influencing the heating, cooling, and chemistry of the region, 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 narrates a different, but equally chaotic tale. This clumpy matter represented in red hides much younger objects than those on the left: 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 the protostars accumulate matter and increase their mass, they eject outflows of superheated material. These outflows interact with the dense, gray matter that the protostars are wrapped within, creating shocks that cause the textured appearance. The red glow is also the result of the interaction, just like the outflows of the central pre-main-sequence star on the golden cavity to the left of the region. Multiple overflows from multiple stars overlap from our point of view, leading to the chaotic appearance.
[Image description: A cluster of many stars that display Webb’s unique eight-pronged diffraction pattern. At its center is a yellow star with the largest diffraction pattern. To the left of the star, there is a region filled with yellow dust and gas that extends from the star to the left border of the image, covering about two-thirds of the image. Several blue stars of different sizes are embedded within this region. The top third, which lies outside of the yellow region, holds a few bright protostars, within dense gray gas. Those stars illuminate the gas, making it appear blue. To the right of the central star, there is a clumpy, flame-like plume of red dust and gas with protostars that emit a soft white light within. The plume is surrounded by more dense gray gas and dust. There are several background galaxies strewn throughout the image]