Webb Telescope Reveals Stunning Details of the “Exposed Cranium” Nebula

New images from the James Webb Space Telescope are offering unprecedented views of a nebula nicknamed the “Exposed Cranium,” officially known as PMR 1. The nebula, surrounding a dying star, exhibits a striking resemblance to a brain within a skull, captivating astronomers and providing valuable insights into stellar evolution.

A Cosmic Cranium Takes Shape

Nebula PMR 1 is a cloud of gas and dust expelled by an aging star as it nears the end of its life. First observed in infrared light over a decade ago by NASA’s Spitzer Space Telescope, the nebula’s intricate details are now being revealed with greater clarity thanks to the advanced capabilities of the Webb Telescope. NASA, STScI, and ESA released combined images from Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) in February 2026.

Unveiling the Nebula with NIRCam and MIRI

Webb’s dual-instrument view is crucial for a comprehensive understanding of PMR 1. NIRCam captures warmer gas and fine structural details, highlighting recent mass-loss events. MIRI, sensitive to cooler dust, reveals a broader envelope surrounding the inner structure, showcasing material expelled during earlier phases. This multi-wavelength approach allows scientists to analyze temperature gradients and the spatial distribution of elements within the nebula, a defining strength of the James Webb Space Telescope.

The Dark Lane and Asymmetric Mass Loss

A prominent dark lane bisects the nebula vertically, dividing it into two opposing lobes. This feature likely marks a dense equatorial region blocking emission from behind, suggesting asymmetric mass loss – the star isn’t ejecting material uniformly. The two lobes aren’t perfectly symmetrical, indicating the outflows have changed over time, with the star experiencing multiple ejection phases. Material near the upper portion of the nebula appears to be pushed outward, potentially due to jet-like outflows.

Dust, Gas, and Stellar Evolution

Infrared observations allow astronomers to penetrate dust clouds and observe regions hidden from visible light. Near-infrared emission traces ionized gas closer to the star, representing recent mass loss, while mid-infrared emission reveals cooler dust distributed over a wider area, representing earlier phases. Analyzing these layers helps reconstruct the nebula’s evolutionary timeline and infer changes in the star’s mass-loss rate. Interactions between faster and slower winds may create shock fronts, potentially explaining some of the filamentary features observed.

The Fate of PMR 1’s Central Star

The ultimate fate of the star at the center of PMR 1 remains uncertain. If the star’s mass is similar to that of the Sun, it will likely become a planetary nebula and eventually a white dwarf. However, if it’s significantly more massive, it could end its life in a supernova. Further study is needed to determine the star’s mass and confirm its evolutionary path.

Significance of PMR 1

Nebulae like PMR 1 play a vital role in galactic evolution. The expelled material contains heavy elements forged within the star, enriching the interstellar medium and providing the building blocks for new stars and planetary systems. The death of one star, seeds the birth of others.