Free Astronomy Magazine May-June 2024

40 MAY-JUNE 2024 ASTRO PUBLISHING origin is a mystery. As you travel farther from the immediate clearings of dust, the deeper red signifies molecular hy- drogen. 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 ex- ample, in Webb’s image, there are two bright, young stars carving out holes in dust above the central nebula, con- nected through diffuse red gas. In visible-light imaging from NASA’s Hubble Space Telescope, these appeared as sepa- rate splotches. Webb’s view in mid-in- frared wavelengths also illustrates a new per- spective 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, be- longing to the surround- ing 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. T his 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 a hotbed of star formation and home to more than 200 of the hottest, most massive kinds of stars, all in the early stages of their lives. In the MIRI view of NGC 604, there are noticeably fewer stars than Webb’s NIRCam image. This is because hot stars emit much less light at these wavelengths. Some of the stars seen in this image are red supergiants—stars that are cool but very large, hundreds of times the diameter of our Sun. The blue tendrils of material signify the presence of polycyclic aromatic hydrocarbons, or PAHs. [NASA, ESA, CSA, STScI] distance, means NGC 604 gives as- tronomers an opportunity to study these objects at a fascinating time early in their life. In Webb’s near-infrared NIRCam im- age, the most noticeable features are tendrils and clumps of emission that appear bright red, extending out from areas that look like clear- ings, or large bubbles in the nebula. Stellar winds from the brightest and hottest young stars have carved out these cavities, while ultraviolet radi- ation 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 sig- nify the presence of carbon-based molecules known as polycyclic aro- matic hydrocarbons, or PAHs. This material plays an important role in the interstellar medium and the for- mation of stars and planets, but its !