Webb telescope captures huge star-forming complex

NASA/ESA/CSA This image from the James Webb Space Telescope shows a vast region of bright gas and plasma in our Milky Way’s satellite galaxy, the Large Magellanic Cloud (LMC).

This nebula, known as N79, is a region of interstellar atomic hydrogen that is ionized, captured here by Webb’s Mid-Infrared Instrument (MIRI).

N79 is a massive star-forming complex spanning approximately 1,630 light-years in the generally unknown southwestern region of the LMC. N79 is often thought to be a smaller version of 30 Doradus (also known as the Tarantula Nebula), one of Webb’s recent targets. Research shows that the star formation potential in N79 is twice that of 30 Doradus over the past 500,000 years.

This particular image focuses on one of the three giant molecular cloud complexes, called N79 South (S1 for short). The distinctive “starburst” pattern around this bright object is a series of diffraction peaks. ESA explained in a statement that all telescopes that use mirrors to collect light, as Webb does, have these types of artifacts that arise from the telescope’s design.

In Webb’s case, the six largest starburst peaks appear due to the hexagonal symmetry of the 18 segments of Webb’s primary mirror. Such patterns are only noticeable around compact, very bright objects, where all the light comes from a single spot. Most galaxies, although they appear very small to our eyes, are darker and more diffuse than a star and so do not show this pattern.

In the longer wavelengths of light captured by MIRI, Webb’s view of N79 shows the region’s bright gas and dust. This is because mid-infrared light is able to reveal what is happening inside the clouds (whereas shorter wavelengths of light will be absorbed or scattered by the nebula’s dust particles). Some still embedded protostars are also visible in this region.

Such star-forming regions are of interest to astronomers because their chemical composition is similar to the giant star-forming regions that were observed when the universe was only a few billion years old and star formation was at its peak. The star-forming regions in our Galaxy do not form stars at the same rate as N79 and have a different chemical composition. Webb now gives astronomers the opportunity to compare and contrast observations of star formation in N79 with the telescope’s deep observations of distant galaxies in the early universe.

These observations of N79 are part of a Webb program that studies the evolution of circumstellar disks and envelopes of forming stars across a wide range of masses and at different evolutionary stages. Webb’s sensitivity will allow scientists to detect planet-forming dust disks around stars with masses similar to our Sun at the distance of the LMC for the first time.