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Peering Into the Tendrils of NGC 604 with NASA’s Webb

At the center of the image is a nebula on the black background of space. The nebula is comprised of clumpy, red, filamentary clouds. At the center-right of the red clouds is a large cavernous bubble, and at the center of the bubble there is an opaque blueish glow with speckles of stars. At the edges of the bubble, the dust is white. There are several other smaller cavernous bubbles at the top of the nebula, including two tiny cavities at the top center of the image. There are thousands of stars that fill the surrounding area outside the nebula, most of them are yellow or white. At 11 o’clock and 6 o’clock there are extremely bright stars with 8 diffraction spikes. There are also some smaller, red stars and a few disk-shaped galaxies scattered across the image.

Star-forming region NGC 604.

Credits: NASA, ESA, CSA, STScI

The formation of stars and the chaotic environments they inhabit is one of the most well-studied, but also mystery-shrouded, areas of cosmic investigation. The intricacies of these processes are now being unveiled like never before by NASA’s James Webb Space Telescope.

Two new images from Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) showcase star-forming region NGC 604, located in the Triangulum galaxy (M33), 2.73 million light-years away from Earth. In these images, cavernous bubbles and stretched-out filaments of gas etch a more detailed and complete tapestry of star birth than seen in the past.

Sheltered among NGC 604’s dusty envelopes of gas are more than 200 of the hottest, most massive kinds of stars, all in the early stages of their lives. These types of stars are B-types and O-types, the latter of which can be more than 100 times the mass of our own Sun. It’s quite rare to find this concentration of them in the nearby universe. In fact, there’s no similar region within our own Milky Way galaxy.

This concentration of massive stars, combined with its relatively close distance, means NGC 604 gives astronomers an opportunity to study these objects at a fascinating time early in their life.

This image from NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) of star-forming region NGC 604 shows how stellar winds from bright, hot, young stars carve out cavities in surrounding gas and dust.

NASA, ESA, CSA, STScI

In Webb’s near-infrared NIRCam image, the most noticeable features are tendrils and clumps of emission that appear bright red, extending out from areas that look like clearings, or large bubbles in the nebula. Stellar winds from the brightest and hottest young stars have carved out these cavities, while ultraviolet radiation ionizes the surrounding gas. This ionized hydrogen appears as a white and blue ghostly glow.

The bright orange-colored streaks in the Webb near-infrared image signify the presence of carbon-based molecules known as polycyclic aromatic hydrocarbons, or PAHs. This material plays an important role in the interstellar medium and the formation of stars and planets, but its origin is a mystery. As you travel farther from the immediate clearings of dust, the deeper red signifies molecular hydrogen. This cooler gas is a prime environment for star formation.

Webb’s exquisite resolution also provides insights into features that previously appeared unrelated to the main cloud. For example, in Webb’s image, there are two bright, young stars carving out holes in dust above the central nebula, connected through diffuse red gas. In visible-light imaging from NASA’s Hubble Space Telescope, these appeared as separate splotches.

At the center of the image is a nebula on the black background of space. The nebula is comprised of wispy filaments of light blue clouds. At the center-right of the blue clouds is a large cavernous bubble. The bottom left edge of this cavernous bubble is filled with hues of pink and white gas. There are several other smaller cavernous bubbles at the top of the nebula, including two tiny cavities at the top center of the image. There are hundreds of dim stars that fill the surrounding area of the nebula.

This image from NASA’s James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) of star-forming region NGC 604 shows how large clouds of cooler gas and dust glow in mid-infrared wavelengths. This region is home to more than 200 of the hottest, most massive kinds of stars, all in the early stages of their lives.

NASA, ESA, CSA, STScI

Webb’s view in mid-infrared wavelengths also illustrates a new perspective into the diverse and dynamic activity of this region. In the MIRI view of NGC 604, there are noticeably fewer stars. This is because hot stars emit much less light at these wavelengths, while the larger clouds of cooler gas and dust glow. Some of the stars seen in this image, belonging to the surrounding galaxy, are red supergiants – stars that are cool but very large, hundreds of times the diameter of our Sun. Additionally, some of the background galaxies that appeared in the NIRCam image also fade. In the MIRI image, the blue tendrils of material signify the presence of PAHs.

NGC 604 is estimated to be around 3.5 million years old. The cloud of glowing gases extends to some 1,300 light-years across.

Explore Webb's images of NGC 604 with Dr Jane Rigby (Webb Senior Project Scientist). Credit: NASA

The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

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