NASA’s James Webb Space Telescope has captured the sharpest infrared images to date of a magnified portion of one of the most distinctive objects in the sky, the Horsehead Nebula. These observations show the top of the “horse’s mane” or edge of this iconic nebula, which is about 0.8 light-years across, in a completely new light, capturing the complexity of the region with unprecedented spatial resolution.
The new images from the Webb telescope, captured within the framework of the Webb GTO 1192 program and published yesterday in the scientific journal Astronomy & Astrophysicsshow a portion of the sky in the constellation Orion, on the western side of a dense region known as the Orion B molecular cloud.
Located 1,300 light years away, the Horsehead Nebula, also known as Barnard 33, It arises among turbulent waves of interstellar dust and gas. The ethereal clouds that appear blue at the bottom of the image are dominated by cold molecular hydrogen, while the red wisps extending above the main nebula represent mostly atomic hydrogen gas.
Origin of the nebula
The nebula, formed from the collapse of a cloud of interstellar gas and dust, shines because it is illuminated by a nearby hot star, Sigma Orionis. The gas clouds surrounding Horsehead have now dissipated, but the protruding pillar is made up of thick clumps of material and is therefore more difficult to erode.
Astronomers estimate that The nebula has about five million years left before it too disintegrates. The new Webb telescope view focuses on the illuminated edge of the top of the nebula’s distinctive structure of dust and gas.
The Horsehead Nebula is a well-known photodissociation region or PDR, where ultraviolet (UV) light from young, massive stars creates a warm, mostly neutral area of gas and dust between the fully ionized gas surrounding massive stars and the clouds in which they are born. This ultraviolet radiation strongly influences the chemistry of these regions and acts as an important source of heat.
These regions occur where the interstellar gas is dense enough to remain largely neutral, but not dense enough to prevent the penetration of ultraviolet light from massive stars. The light emitted by such PDRs provides a unique tool to study the physical and chemical processes that drive the evolution of interstellar matter in our galaxy. and throughout the universe from the early era of active star formation to the present.
Due to its proximity and its particular geometry, the Horsehead Nebula is an ideal target for astronomers to study the physical structures of PDRs, the molecular evolution of gas and dust within their respective environments, as well as transition regions among them. Likewise, it is considered one of the best regions of the sky to study how radiation interacts with interstellar matter.
Cutting-edge optical instruments
Using Webb’s MIRI and NIRCam instruments, an international team of astronomers has revealed for the first time the small-scale structures of Horsehead’s illuminated edge, which is about 0.8 light-years in diameter. As the ultraviolet light evaporates the dust cloud, the dust particles are dragged out of the cloud and transported along with the heated gas. Webb has detected a network of fine features that track this movement. The observations have also allowed astronomers to investigate how the dust blocks and emits light, and to better understand the multidimensional shape of the nebula.
Now, astronomers intend to study the spectroscopic data obtained to obtain information on the evolution of the physical and chemical properties of the material observed through the nebula.
Published: 4/30/2024
