When stars form in the Universe, they’re created in giant bursts.

When giant molecular clouds collapse, new stars form all at once.

The highest-density gas creates the greatest numbers of high-mass stars.

These include the hottest, bluest, shortest-lived stars: O-class and B-class stars.

The most massive stars known exist within the Tarantula Nebula, 165,000 light-years away.

However, young, massive clusters are rare within the Milky Way.

Westerlund 2 is our closest example, with 37 very massive stars identified up to 100 solar masses.

It’s a unique cosmic laboratory in terms of size, stars, and proximity: just 14,000 light-years distant.

Previously, studies of planet-forming disks were restricted to nearby, lower-mass stars.

Those observed disks are currently creating planets, which multiple instruments have independently identified.

However, the central regions of massive clusters may render planet formation impossible.

Very massive stars are so hot that potentially planet-forming dust has already evaporated away or had its composition altered.

As a result, they cannot create the stable, early structures that eventually create planets.

Hubble’s near-infrared instruments suggest that planets will never exist around these stars.

NASA’s upcoming James Webb Space Telescope, launching next year, will determine where planets do and don’t form.

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