The NASA/ESA/CSA James Webb Space Telescope has captured a detailed infrared view of NGC 7129, a stellar nursery roughly 3,300 light-years from Earth. The image reveals stars that had been obscured by dust, along with cavities, bow shocks and other signs of a turbulent environment in which young stars are actively reshaping the cloud around them.
NGC 7129 is not a uniform field of newly formed stars. It contains objects at different stages of development, from comparatively mature pre-main-sequence stars to younger protostars still hidden in dense material. That mix gives astronomers a view of how stellar birth changes a molecular cloud over time: outflows and radiation can disperse gas in some places while compressing it in others, creating conditions that can support further star formation.
Infrared vision opens the cloud
Webb observed the region in infrared light, which can pass through dense matter that scatters or absorbs other wavelengths. This capability is especially useful in stellar nurseries, where dust and gas conceal many of the objects astronomers want to study.
The resulting view shows a collection of young stars at several developmental stages. More massive stars form and evolve faster than less massive ones, so a single stellar nursery can contain objects that have already changed their surroundings substantially alongside much younger objects that remain embedded in dusty clumps.
At the center of the image is LkH(alpha) 234, the most luminous central star in the region and the source of the image’s most prominent diffraction pattern. ESA describes it as a pre-main-sequence star with a mass estimated at about five to eight times that of the Sun. Such stars have largely completed the process of gathering mass and are contracting under gravity, causing their temperatures to rise. In time, LkH(alpha) 234 is expected to begin fusing hydrogen in its core, as the Sun does.
A cavity carved by a young star
One of the image’s clearest structures lies to the left of LkH(alpha) 234: a gold-colored cavity spanning about 3.5 light-years. It records the star’s influence on its surroundings. Outflows from an earlier phase of the star’s life carved into the dense molecular cloud, while the star’s light and those outflows energised gas and caused it to glow.
Outflows are a familiar part of early stellar evolution. Material moving away from a young star can push into the surrounding cloud, opening channels and cavities. In NGC 7129, ESA says the activity has blown away some of the hydrogen gas. But not all of the gas is simply lost. A substantial amount is compressed, a process that can help establish conditions for additional stars to form.
Several young stars are visible inside that cavity. Like the central star, some are pre-main-sequence objects, and they produce stellar winds of their own. Nearby bow shocks trace where those winds collide with and push into energetic gas. The curved structures are visual evidence of motion and pressure: material from a young star meets its environment and produces a compressed boundary.
Where stellar activity changes cloud chemistry
The central star and its embedded neighbors have created a hot environment that presses against colder, denser molecular gas. The boundary between them is known as a photodissociation region. In that zone, molecules of hydrogen are broken down into individual atoms.
That process is not merely a visual detail. Heating, cooling and chemical changes in the cloud shape how it evolves. In NGC 7129, the group of young stars is gradually eroding its molecular environment. ESA says the scene offers insight into how such clouds change over millions of years, as stellar radiation and outflows alter the material from which stars are born.
The image therefore captures both destruction and creation in the same setting. Gas is being cleared from some regions, but compression and changing conditions can also influence later star formation. The balance between those effects is part of what makes stellar nurseries such important laboratories for understanding the development of star clusters.
A younger and more obscured population
The area to the right of the central star tells a different story. It appears as clumpy red material and conceals younger objects than the population on the left. These are protostars: objects at an earlier stage of stellar development, still embedded in the dense matter from which they are forming.
The contrast across the image makes NGC 7129 particularly instructive. On one side, stars have already cleared a large cavity and are producing winds that form bow shocks. On the other, dusty material still hides much younger stellar objects. Webb’s infrared sensitivity allows both parts of that sequence to be seen in a single observation.
The telescope cannot show a star’s entire life story in one image, but it can place different stages of that story in the same cosmic landscape. Observers can compare the exposed, more evolved young stars with the red, obscured regions that contain protostars, then connect the structures around them to the processes altering the cloud.
A portrait of active star formation
Webb’s new view is a reminder that stellar nurseries are dynamic environments. They are shaped by gravity, radiation, winds and outflows, rather than being passive clouds waiting for stars to emerge. LkH(alpha) 234 and its neighbors are already changing NGC 7129, while the protostars hidden nearby represent an earlier phase of the same broader process.
By looking through dust in infrared light, Webb has made that interaction unusually clear. The image shows a region where young stars illuminate, excavate and chemically transform their surroundings—and where dense pockets of material still preserve the next stages of stellar birth.
This article is based on reporting by esa.int. Read the original article.
Originally published on esa.int
