Webb reveals emerging stellar nurseries and individual stars that are completely hidden in visible-light pictures. Because of Webb’s sensitivity to infrared light, it can peer through cosmic dust to see these objects. Protostellar jets, which emerge clearly in this image, shoot out from some of these young stars. The youngest sources appear as red dots in the dark, dusty region of the cloud. Objects in the earliest, rapid phases of star formation are difficult to capture, but Webb’s extreme sensitivity, spatial resolution, and imaging capability can chronicle these elusive events.
These observations of NGC 3324 will shed light on the process of star formation. Star birth propagates over time, triggered by the expansion of the eroding cavity. As the bright, ionized rim moves into the nebula, it slowly pushes into the gas and dust. If the rim encounters any unstable material, the increased pressure will trigger the material to collapse and form new stars.
Conversely, this type of disturbance may also prevent star formation as the star-making material is eroded away. This is a very delicate balance between sparking star formation and stopping it. Webb will address some of the great, open questions of modern astrophysics: What determines the number of stars that form in a certain region? Why do stars form with a certain mass?
Webb will also reveal the impact of star formation on the evolution of gigantic clouds of gas and dust. While the effect of massive stars – with their violent winds and high energy – is often apparent, less is known about the influence of the more numerous low-mass stars. As they form, these smaller stars create narrow, opposing jets seen here, which can inject a lot of momentum and energy into the clouds. This reduces the fraction of nebular material that seeds new stars.
Up to this point, scientists have had very little data about the influence of the multitude of young and more energetic low-mass stars. With Webb, they will be able to obtain a full census of their number and impact throughout the nebula.