The Tarantula Nebula, also called 30 Doradus, is the brightest star-forming region in our part of the galaxy. It’s in the Large Magellanic Cloud (LMC) and contains the most massive and hottest stars we know of. The Tarantula Nebula has been a repeat target for the Hubble since the telescope’s early years.
Star formation is an extremely detailed process, and the Tarantula Nebula’s bright star-forming regions are a natural laboratory for studying the interplay between stars, gas, and dust. This image comes from two Hubble observing programs aimed at 30 Doradus. Scylla studies how interstellar dust interacts with starlight in a variety of environments, and Ulysses studies the stars themselves in 30 Doradus.
30 Doradus is chock full of interesting observing targets. This featured image mostly shows the star cluster NGC 2060. NGC 2060 is a loose star cluster within one of the nebula’s superbubbles, a cavity hundreds of light years across. The cluster is approximately 10 million years old.
For context, the image below is a wide image of the Tarantula Nebula showing where the Hubble image is located.
Astronomers can study multiple aspects of star formation in the region. Multiple observing programs by multiple telescopes over the years have studied how hot, young, massive stars carve out bubbles in the gas. They’ve also studied oddball rapidly rotating stars. They’ve studied the dark lanes of thick dust and Bok globules. There are even supernova remnants in the regions, as well as HII regions. Almost any object of study is present in the region, and there’s even a stellar-mass black hole. The region is scientifically important because it allows multi-epoch surveys, which means astronomers can study stars at all stages of evolution.
The rapidly rotating star in the image is named VFTS 102. VFTS (VLT-FLAMES Tarantula Survey) is the name of a star survey in the region that sought to characterize more than 900 stars. One of the things VFTS studied is how rotation affects the evolution of stars. VFTS 102 is the second fastest-rotating massive star that we know of, and it rotates at about two million kilometres per hour. It spins so rapidly that the centripetal force flattens the star, forming a disk of stellar material around itself. It may have gained such a high speed due to interactions with a binary companion.
TLD1 in the image is a cluster of young stars that average about 3.3 million years old. These stars have blown away most of the gas in their vicinity and are clearly visible as a clump of hot blue stars. When the giant molecular clouds collapsed to form 30 Doradus, they fragmented into sheets, filaments, and clumps where stars subsequently formed. TLD1 likely formed where sheets and filaments intersected. That can funnel star-forming gas into a smaller region, giving rise to clusters of coeval stars.
Two HII regions are labelled in the image, although some consider the entire nebula to be an HII region. HII regions are ionized hydrogen. They’re created when newly-formed, massive young stars ionizes hydrogen with powerful UV radiation. The UV causes the hydrogen atoms to lose their electrons, giving the atom a positive charge. HII regions can reach temperatures of up to 10,000 Kelvin (1700 C; 3100 F.)
HII gas is part of the star-formation process. The massive young stars that create the HII also carve cavities out of the surrounding gas. Since the HII is hotter, it flows into these cavities. It can slam into denser, colder gas on the edge of these cavities, and the resulting shock wave can trigger new starbirth. The TLD1 cluster in the image started out as an HII region, and the stars that formed there eventually blew all the hydrogen gas away. The HII regions in the image will likely be star clusters in the future.
One of the joys of new telescopes like the James Webb Space Telescope is that it gives us a new, powerful view of a familiar region or object in space. That’s true of the JWST and the Tarantula Nebula. The JWST’s power revealed tens of thousands of stars never seen before. These stars are shrouded by dust that remained impenetrable until the JWST started operating.
Astronomers from the past would be shocked at the quality of astronomical images available today. With a few mouse clicks, anyone who is interested can gaze in wonder at regions like the Tarantula Nebula. But it wasn’t always so. Only a few decades ago, crude images with hand-drawn labels were the tools of the astronomical trade.
The Tarantula Nebula will keep attracting our attention for a long time to come. Astronomers sometimes refer to it as a “Rosetta Stone” because it contains everything from clouds of cold gas—the precursors of stars—all the way up to supernova remnants, the end-states of massive stars. Its proximity means astronomers can study the big picture of how star clusters and gas and bubbles all act together, as well as individual stars in detail.
30 Doradus truly is a laboratory of star birth and evolution.