The Horsehead Nebula is one of the highlights of the Orion constellation. This dark nebula is difficult to observe even with an extremely good telescope. But that was without counting on James Webb, who managed to capture him more clearly than ever. The complexity of the striking celestial body comes to us in unparalleled detail.
Webb’s new photos show part of the universe in the constellation Orion – also called ‘the Hunter’ – on the western side of the molecular cloud Orion B. From turbulent waves of dust and gas, the Horsehead Nebula, better known, rises there as Barnard 33, which is about 1,300 light-years away from Earth.
Horse head
The nebula formed from an interstellar cloud of matter that collapsed. The whole thing glows because it is illuminated by a nearby hot star. The gas clouds around the Horse’s Head have already disappeared, but the protruding pillar is made of thick clumps of material that do not erode away so easily. Astronomers estimate that the Horsehead has about 5 million years left before it disintegrates. Webb’s new images mainly show the illuminated edge of the upper part of the nebula’s distinctive dust and gas structure.
PDR
The Horsehead Nebula is one of the best-known photodissociation regions (PDRs). In such a region, ultraviolet light emitted by massive, young stars creates a largely neutral, warm region of gas and dust. Massive stars are much more dense than our Sun. These types of stars release so much energy that they extremely heat all the material around them and cause chemical reactions. Fully ionized gas surrounds these stars and the clouds in which they are born. The ultraviolet radiation has a strong influence on the gas formation in these areas and acts as the main heat source.
Penetration of ultraviolet light
The phenomenon occurs where interstellar gas is dense enough to remain neutral, but not dense enough to prevent the penetration of ultraviolet light from massive stars. The light emitted by these PDRs gives us a beautiful view of the physical and chemical processes that drive the evolution of interstellar matter in many places in the universe, as well as in our own Milky Way Galaxy. This happened many billions of years ago and continues to this day.
Because of its proximity and beautiful geometry, the Horsehead Nebula is an ideal target for astronomers to study the physical structures of PDRs, the evolution of the chemical properties of cosmic gas and stardust, and the transition regions between them. Astronomers consider it one of the best celestial bodies to learn about how radiation and interstellar matter interact.
Detailed structures
Webb is the largest, most expensive and most powerful telescope man has ever launched into space. An international team of astronomers has been able to image the small-scale, detailed structures of the illuminated edge of the Horse’s Head for the first time thanks to the groundbreaking technology of the Webb telescope. They also discovered a network of striated structures extending perpendicular to the PDR front. These networks appear to contain dust particles and ionized gas that are carried along in the nebula’s evaporation trail.
Spectroscopy
After this, the scientists plan to study the nebula’s spectroscopic data. The purpose of this analysis – which examines substances using their electromagnetic spectrum – is to learn more about the evolution of the physical and chemical properties of the observed material in the Horsehead Nebula.
