Exploring the Star Birth Hub in the Small Magellanic Cloud with James Webb
Within the neighbouring dwarf galaxy known as the Small Magellanic Cloud (SMC), an extraordinary region of star formation known as NGC 346 has captured the attention of astronomers worldwide. NGC 346, the brightest and most extensive star-forming area in the SMC, has been a subject of intense study using a variety of telescopes. NASA’s Hubble Space Telescope provided a visible-light view, showcasing thousands of stars. Subsequently, NASA’s James Webb Space Telescope has offered a near-infrared perspective, revealing both cool and warm dust. Now, Webb has turned its mid-infrared gaze toward NGC 346, unveiling intricate streams of gas and dust adorned with luminous patches housing young protostars.
One of the remarkable capabilities of NASA’s James Webb Space Telescope is its ability to provide astronomers with unprecedented insights into regions where new stars are born. The most recent example is NGC 346, presented in a new image captured by Webb’s Mid-Infrared Instrument (MIRI). NGC 346 represents the largest and brightest star-forming region within the Small Magellanic Cloud.
The Small Magellanic Cloud (SMC) stands as a satellite galaxy of our Milky Way, visible to the naked eye in the southern constellation Tucana. In contrast to our own galaxy, this diminutive companion possesses a more primitive composition, characterized by a scarcity of heavy elements. These heavy elements, such as silicon and oxygen, are typically produced within stars through processes like nuclear fusion and supernova explosions.
Due to the origin of cosmic dust from these heavy elements, scientists initially anticipated that the SMC would exhibit limited quantities of dust. However, the recent MIRI image, along with a previous image of NGC 346 captured by Webb’s Near-Infrared Camera, challenges this assumption by revealing a substantial presence of dust within the region.
In the representative-color image, we can discern blue tendrils tracing emissions from various materials, including dusty silicates and sooty chemical molecules known as polycyclic aromatic hydrocarbons (PAHs). Meanwhile, more diffuse red emissions emanate from warm dust, primarily heated by the region’s brightest and most massive stars at its core. An intriguing arc on the image’s center-left side may result from the reflection of light from the star situated near the arc’s center. (Similar yet fainter arcs appear in association with stars located in the lower-left and upper-right sections of the image.) Lastly, bright patches and filaments spotlight areas teeming with numerous protostars. By scrutinizing the reddest stars within the region, researchers have pinpointed 1,001 sources of light, the majority of which are young stars still enshrouded within their dusty cocoons.
The fusion of Webb’s data in both the near-infrared and mid-infrared spectra allows astronomers to construct a more comprehensive census of the stars and protostars populating this dynamic region. These findings hold significant implications for our comprehension of galaxies that existed billions of years ago, particularly during a cosmic era known as “cosmic noon.” During this epoch, star formation was at its zenith, and concentrations of heavy elements were lower, akin to the conditions observed in the SMC.
In summary, NGC 346 in the Small Magellanic Cloud continues to be an astronomical treasure trove, offering fresh insights into the intricate processes of star birth and cosmic evolution. Thanks to the remarkable capabilities of the James Webb Space Telescope, we are delving deeper into the cosmos and uncovering its well-guarded secrets.
Photo: NASA
For more info, please visit https://webbtelescope.org/contents/news-releases/2023/news-2023-145
