Star-Forming Region NGC 604 as seen by Webb

Click the image for higher resolution (4.2 MB)

This image from the 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.

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 known as 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.

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 ionises the surrounding gas. This ionised hydrogen appears as a white and blue ghostly glow.

The bright orange 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 further 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 the Hubble Space Telescope, these appeared as separate splotches.

Webb's view in mid-infrared wavelengths also illustrates a new perspective on the diverse and dynamic activity of this region. Some of the stars seen in this image from 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.

NGC 604 is estimated to be around 3.5 million years old. The cloud of glowing gases extends to some 1300 light-years across.

Image Credit: NASA, ESA, CSA, STScI

Image enhancement: Jean-Baptiste Faure