Webb captures commotion from nebula’s stellar jets
Webb captures commotion from nebula’s stellar jets
Webb’s infrared gaze and high resolution reveals stars at various stages in their life cycles
A technicolor dreamscape is revealed in this new image from the NASA/ESA/CSA James Webb Space Telescope. It portrays a stellar nursery known as NGC 7129, a nebula that holds numerous protostars and stars within its fields of gas and dust. 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 surrounding environment.
A cauldron of cosmic creation is being revealed in a new image from Webb, which has unveiled numerous stars formerly hidden by clouds of dust in a stellar nursery known as NGC 7129, which resides about 3,300 light-years from Earth.
Stars, the engines of elemental creation, have life cycles that begin with their birth in molecular clouds – cold, dense regions of dust and gas. Because of these dusty cocoons, young stars are often impossible to view by many telescopes, particularly those incapable of capturing infrared light. Webb, however, has a high degree of infrared sensitivity, allowing astronomers to peer through that dust and study the beginning of the star life cycle.
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 (pronounced Lick-H-alpha). This star, which sports the image’s most prominent diffraction pattern, is a pre-main-sequence star weighing around 5 to 8 times the mass of our Sun. Pre-main-sequence stars like these have mostly finished gathering mass and are 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 stars are visible within the cavity. Several of them are also pre-main-sequence and emit 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 create their own, smaller cavities.
Together, the central and embedded stars also create the sharp ridge seen at the top of the golden cavity. Their light generates a hot environment that pushes against the colder and denser molecular gas outside the cavity, and creates a boundary known as a photodissociation region. In this region, the molecules of hydrogen break down into atoms. By influencing the temperature 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, grey matter the protostars are wrapped within, creating shocks that cause a textured appearance. The red glow is also the result of the interaction. Multiple outflows from multiple stars overlap from our point of view, leading to the scene’s chaotic look.
More of these protostellar outflows can be seen at the upper left of the image, near a blue-colored nebula. The centre of this blue region hosts a protostar surrounded by a donut-shaped disk of material. This disk casts a shadow against the surrounding nebula, reminiscent of a similar structure known as the “Bat Shadow” that was observed by the NASA/ESA Hubble Space Telescope.
Webb’s high spatial resolution reveals many rich structures in the region’s gas. Astronomers will continue to use this Webb data to study how the stars and protostars in this region influence the surrounding gas and dust.
NGC 7129 (NIRCam image)
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