Meet N79: home to the Local Group’s newest super star cluster

All throughout cosmic history, star-formation has illuminated the darkness of deep space.

Looking at the same region of space in three different wavelengths of light, a short-wavelength infrared view, a long-wavelength infrared view, and a narrowband view at a wavelength of 1.87 microns, reveals many different features within the same region of the Orion Nebula. The bright, glowing features at long wavelengths of light indicate large amounts of modestly cool neutral matter, pointing to star-formation still being ongoing in those regions. Actively star-forming regions create not only singlet stellar systems like our own, but also binary, trinary, and even richer multi-star systems as well.

For more than 13 billion years, our Universe has been fully reionized: transparent to starlight.

For the first 550 million years of the Universe, neutral, light-blocking atoms persist ubiquitously in the space between galaxies, continuing what’s known as the cosmic dark ages. Once the last of that neutral matter becomes reionized, starlight can propagate freely through the Universe, marking the end of the reionization epoch. In some locations, reionization happens earlier or later than average, but by the time the Universe is ~800 million years old, it should be fully reionized.

Although star-formation has slowed to a trickle today, it was 30-50 times more vigorous long ago.

An artistic representation of a starburst galaxy, where the entire galaxy itself behaves as a star-forming region, using data from the FIRE (Feedback in Realistic Environments) simulation that includes strong bursts of star-formation. For the first ~3 billion years of cosmic history, the star-formation rate rose and rose until reaching a peak, but has fallen off significantly in the ~10-11 billion years since. Whether starburst galaxies become red-and-dead or will form new stars later on depends on factors we have not yet fully understood, especially at early times.

Instead of today’s modern small star-forming regions, giant ones were the norm 6+ billion years ago.

When major mergers of similarly-sized galaxies occur in the Universe, they form new stars out of the hydrogen and helium gas present within them. This can result in severely increased rates of star-formation, similar to what we observe inside the nearby galaxy Henize 2-10, located 30 million light years away. This galaxy will likely evolve, post-merger, into another disk galaxy if copious amounts of gas remains within it, or into an elliptical if all or nearly all of the gas is expelled by the current starburst. Starburst events like this were much more common earlier in cosmic history than they are today.

Today, open star clusters are typical sites for new stars.

The open star cluster NGC 290, as imaged by Hubble. When new stars form, they form with a variety of masses, colors, luminosities, and other properties, with most open star clusters, at present, producing hundreds to thousands of new stars. More massive examples are possible, but are only common much earlier in cosmic history. At late times, these more modest star clusters are the norm, with more massive, super star clusters serving as a modern-day rarity.

But long ago, super star clusters, with 100,000+ stars each, dominated.

This artist’s illustration shows what a super star cluster, similar to H72.97-69.39 within N79, ought to look like once no more gas, dust, protostellar, or outflowing material is in the way.

Until the JWST era, only three super star clusters were known within the entire Local Group.

The image shows the central region of the Tarantula Nebula in the Large Magellanic Cloud. The young and dense star cluster R136 can be seen near the center of the image. The tidal forces exerted on the Large Magellanic Cloud by the Milky Way are triggering a wave of star-formation in there, which happens to be the largest star-forming region known in the Local Group. R136a1, at the cluster’s center, is the most massive single star known, with approximately 260 times the mass of our Sun.

A fourth one — lying inside N79 in the Large Magellanic Cloud — has just been found.

One of the largest, most active regions of star formation is the Tarantula Nebula within the Large Magellanic Cloud: a satellite galaxy of the Milky Way. Two regions, 30 Doradus and N79, are now known to house super star clusters, with R136 inside 30 Doradus being the largest and N79 housing the youngest.

Known as H72.97-69.39, it’s the youngest one ever discovered: under 100,000 years old.

This composite image takes advantage of both JWST NIRCam and long-wavelength ALMA (radio) data, creating a view of the inner portion of the star-forming region N79 in the Large Magellanic Cloud. Over 1550 young stars have been found surrounding a single massive protostar.

Viewed with JWST’s MIRI and NIRCam, over 1500 protostars have been identified inside.

This side-by-side image shows JWST MIRI (left) and annotated NIRCam (right) views, showing filaments of gas, a number of young stellar objects (or protostars), and showcases the highest-resolution views ever obtained of this star-forming region.

The most massive protostars are found within the cluster’s greatest active star-formation site.

This ALMA image shows sulfur monoxide (in yellow), as well as redshifted (red) and blueshifted (blue) outflows coming from the central 5 light-years of the super star cluster H72.97-69.39 within N79. Overlaid is the location of several identified JWST protostars, including a large, massive one that’s over 500,000 times more luminous than the Sun.

ALMA shows carbon and sulfur monoxide outflows within the innermost 5 light-years.

Back in 2019, ALMA data showed the kinematics of material in N79 surrounding what was then a super star cluster candidate known as H72.97-69.39. Now, in 2025, JWST data has strengthened the case for a super star cluster.

Inside, star-formation is 200-400% more rapid than within R136.

The near-infrared view of the Tarantula Nebula taken with JWST is higher in resolution and broader in wavelength coverage than any previous view. It heavily expands on what Hubble taught us, and this wide-field view of our neighbor galaxy, the LMC, still showcases just 0.003778 square degrees in the sky. It would take 10.9 million images of this size to cover the entire sky. The super star cluster to the right of center, R136, is the largest, most massive new star cluster found within our entire Local Group of galaxies, and is expected to be a prime example of a newly forming globular star cluster.

Chandra X-ray observations confirm its young age.

This composite image shows hard X-rays, soft X-rays, and ALMA (radio wave) data all together at the core of star-forming region N79. A single massive protostar, 500,000+ times the brightness and 60,000+ times the volume of our Sun, may be triggering the formation of 1000+ new stars/protostars.

A central protostar shines 500,000+ times brighter than our Sun.

The ALMA data of this region shows carbon monoxide (with carbon-13) outflows from the central super star cluster region of N79, with red contours identifying away-moving outflows and blue contours identifying toward-moving outflows. The determined timescale of the outflows, based on this data, indicates an age of just 65,000 years: the youngest super star cluster ever found.

It may serve as the catalyst for thousands of newborn stars inside.

This image shows individually identified massive stars within the super star cluster H72.97-69.39, as confirmed with JWST NIRCam data at 1.15, 2.00, and 2.77 microns.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.