Star Cluster IC 348 (NIRCam image annotated)

This image from the NIRCam (Near-Infrared Camera) instrument on NASA’s James Webb Space Telescope shows the central portion of the star cluster IC 348. Astronomers combed the cluster in search of tiny, free-floating brown dwarfs: objects too small to be stars but larger than most planets. They found three brown dwarfs that are less than eight times the mass of Jupiter, which are circled in the main image and shown in the detailed pullouts at right. The smallest weighs just three to four times as much as Jupiter, challenging theories for star formation.

The wispy curtains filling the image are interstellar material reflecting the light from the cluster’s stars — what is known as a reflection nebula. The material also includes carbon-containing molecules known as polycyclic aromatic hydrocarbons, or PAHs. The bright star closest to the centre of the frame is actually a pair of type B stars in a binary system, the most massive stars in the cluster. Winds from these stars may help sculpt the large loop seen on the right side of the field of view.

[Image description: Image of a star cluster and nebula, with three image details pulled out in square boxes stacked vertically along the right. Main image is showing wispy pink-purple filaments and a scattering of stars. Each of the three boxes along the right corresponds to a small detail, numbered and circled, in the main image. Box 1 (top): A detail from the lower left of the main image shows a pair of small circular pinkish-white spots on a yellowish-brown background. Box 2 (middle): A detail from the middle of the lower part of the main image shows a single small circular pinkish spot on a yellowish-brown background. Box 3: A detail from the lower right edge of the main image shows a small circular pinkish spot on a dark brown background.]