LThe Orion Nebula is one of the most studied areas in our sky. Located in the interstellar constellation Orion, it is so large, so dense and so bright that it can be seen with the naked eye: a vast complex of clouds that give birth and nurture stars.
Header image, click to enlarge: my inner region of the Orion Nebula as seen by the NIRCam instrument on the James Webb Space Telescope. This is a composite image obtained from several filters showing the emission of ionized gas, hydrocarbons, molecular gas, dust and diffuse starlight. (NASA, ESA, CSA, PDRs4All ERS Team/ Salomé Fuenmayor)
Because it is relatively close, 1,344 light-years away, it is one of the most important observational targets in the sky for understanding star formation. Although we have been observing the nebula since its official discovery in 1610, not all of its secrets have yet been revealed.
Recently, the most powerful space telescope currently offered a new look at the heart of the Orion Nebula.
According to astronomers, the new images taken by NIRCam from the James Webb Space Telescope (Webb/JWST) are the most detailed and sharpest we have seen so far. The analysis is ongoing and we should learn some fascinating new things about this incredible part of the galaxy.
According to astrophysicist Els Peeters from Western University in Canada:
We are blown away by the breathtaking images of the Orion Nebula. We started this project in 2017, so we have been waiting for this data for more than 5 years.
These new observations allow us to better understand how massive stars transform the cloud of gas and dust in which they were born. Young massive stars emit large amounts of ultraviolet radiation directly into the birth cloud that still surrounds them, changing the cloud’s physical shape as well as its chemical composition.
It is not yet clear how exactly this works or how it affects the subsequent formation of stars and planets.
Star formation is a very gaseous and dusty process. Young stars are born from dense clumps in clouds of dust and gas that collapse under gravity and begin to collect material from the cloud around them, forming a disk as they go. The very nature of this process makes it hard to see: all that dust and gas blocks the light from escaping to show us what’s inside.
However, long wavelengths of infrared light, the range through which JWST sees the universe, are able to penetrate dust, giving us a view of regions that are impossible to see in longer wavelengths, as short as the visible spectrum. Scientists are therefore very excited to use the telescope to study star formation and discover new details about this process, which so far have been difficult to observe.
The new image focuses on a structure called the “Orion Bar” (Orion Bar), which runs diagonally from top left to bottom right. Light from a cluster of young, hot stars, called the Trapezium Cluster, illuminates the scene from the upper right corner. This intense ionizing ultraviolet light slowly erodes the rod.
Click to enlarge. Annotated version in French of the Orion Nebula. (NASA, ESA, CSA, PDRs4All ERS Team/ Salomé Fuenmayor)
It is one of the processes involved in what astronomers call feedback (feedback) when winds or radiation from a stellar object push away material, reducing or extinguishing star formation. They also produce complex shapes and structures in a molecular cloud, including filaments and voids, both of which were captured in the new image.
Other objects in this image include Bok globules (dense clumps of matter containing new stars) and a growing young star surrounded by a disc of matter. This disk is vaporized from the outside by the radiation from the stars in the Trapezium. Almost 180 of these items, called traffic noise in English to denote the ionized protoplanetary discs, have been found in the Orion Nebula.
The brightest star you see in the image is called θ2 Orionis A, and it is one of the members of a multi-star system next to the Trapezium Cluster, which is also known by the name of θ1 Orionis. Interestingly, θ2 Orionis A is also itself a three-star system.
Although it appears very bright in the JWST image, θ2 Orionis A can only be seen with the naked eye from Earth in areas that are only slightly affected by light pollution. Nevertheless, it is very hot, more than 100,000 times intrinsically brighter than the Sun. Its light reflects off the dust around it, creating a beautiful red glow.
According to astronomer Olivier Berné from the Institute of Space Astrophysics in France
We clearly see several dense filaments. These filamentary structures could support a new generation of stars in the deeper regions of the dust and gas cloud. Star systems already in formation also appear.
Inside its cocoon, young stars with a disk of dust and gas, in which planets form, are seen in the nebula. Small voids carved out by the new stars blown away by the intense radiation and stellar winds from the nascent stars are also clearly visible.
The image to discover in its full resolution on the site for Early release of the Science program Photodissociation Regions for All (PDRs4All ERS Team): The inner Orion Nebula seen with JWST, featured on the Institute for Space Astrophysics website: James Webb Telescope: first images of the Orion Nebula and on the Western University website: Western researchers among the first to capture James Webb Space Telescope images .