The James Webb Space Telescope (Webb) has captured the most detailed and sharpest images ever taken of the inner region of the Orion Nebula, a stellar nursery situated in the constellation Orion 1,350 light-years away from Earth.
The new images released today were targeted by an international collaboration, which includes researchers from Western University.
The inner region of the Orion Nebula as seen by the James Webb Space Telescope’s NIRCam instrument. This is a composite image from several filters that represents emission from ionized gas, hydrocarbons, molecular gas, dust and scattered starlight. Most prominent is the Orion Bar, a wall of dense gas and dust that runs from the top left to the bottom right in this image, and that contains the bright star θ2 Orionis A. The scene is illuminated by a group of hot, young massive stars (known as the Trapezium Cluster) that is located just off the top right of the image. The strong and harsh ultraviolet radiation of the Trapezium cluster creates a hot, ionized environment in the upper right, and slowly erodes the Orion Bar away. Molecules and dust can survive longer in the shielded environment offered by the dense Bar, but the surge of stellar energy sculpts a region that displays an incredible richness of filaments, globules, young stars with disks and cavities.
Credit: NASA, ESA, CSA, PDRs4All ERS Team; image processing Salomé Fuenmayor
Technical details: The image was obtained with the James Webb Space Telescope NIRCam instrument on September 11, 2022. Several images in different filters were combined to create this composite image: F140M and F210M (blue); F277W, F300M, F323N, F335M, and F332W (green); F405N (orange); and F444W, F480M, and F470N (red).
“We are blown away by the breathtaking images of the Orion Nebula. We started this project in 2017, so we have been waiting more than five years to get these data,” said Western astrophysicist Els Peeters.
These images have been obtained as part of the Early Release Science program Photodissociation Regions for All (PDRs4All ID 1288) on Webb. Co-led by Peeters, French National Centre for Scientific Research (CNRS) scientist Olivier Berné, and Institut d’Astrophysique Spatiale (IAS) associate professor Emilie Habart, PDRs4All is an international collaboration which involves a team of more than one hundred scientists in 18 countries, including Western astrophysicists Jan Cami, Ameek Sidhu, Ryan Chown, Bethany Schefter, Sofia Pasquini and Baria Kahn.
Els Peeters
“These new observations allow us to better understand how massive stars transform the gas and dust cloud in which they are born,” said Peeters, a Western astronomy professor and faculty member at the Institute for Earth and Space Exploration.
“Massive young stars emit large quantities of ultraviolet radiation directly into the native cloud that still surrounds them, and this changes the physical shape of the cloud as well as its chemical makeup. How precisely this works, and how it affects further star and planet formation is not yet well known.”
The new images released today reveal numerous spectacular structures inside the nebula, down to scales comparable to the size of the Solar System.
Young star with disk inside its cocoon: Planet forming disks of gas and dust around a young star. These disks are being dissipated or “photo-evaporated” due to the strong radiation field of the nearby stars of the Trapezium creating a cocoon of dust and gas around them. Almost 180 of these externally illuminated photoevaporating disks around young stars (aka Proplyds) have been discovered in the Orion nebula, and HST-10 (the one in the picture) is one of the largest known. The orbit of Neptune is shown for comparison.
Filaments: The entire image is rich in filaments of different sizes and shapes. The inset here shows thin, meandering filaments that are especially rich in hydrocarbon molecules and molecular hydrogen. They are believed to be created by turbulent motions of the gas within the nebula.
θ2 Orionis A: The brightest star in this image is θ2 Orionis A, a star that is just bright enough to be seen with the naked eye from a dark location on Earth. Stellar light that is reflecting off dust grains causes the red glow in its immediate surroundings.
Young star inside globule: When dense clouds of gas and dust become gravitationally unstable, they collapse into stellar embryos that gradually grow more massive until they can start nuclear fusion in their core – they start to shine. This young star is still embedded in its natal cloud.
Credit: NASA, ESA, CSA, PDRs4All ERS Team; image processing Salomé Fuenmayor
Technical details: The image was obtained with the James Webb Space Telescope NIRCam instrument on September 11, 2022. Several images in different filters were combined to create this composite image: F140M and F210M (blue); F277W, F300M, F323N, F335M, and F332W (green); F405N (orange); and F444W, F480M, and F470N (red).
“We clearly see several dense filaments. These filamentary structures may promote a new generation of stars in the deeper regions of the cloud of dust and gas. Stellar systems already in formation show up as well,” said Berné. “Inside its cocoon, young stars with a disk of dust and gas in which planets form are observed in the nebula. Small cavities dug by new stars being blown by the intense radiation and stellar winds of newborn stars are also clearly visible.”
Proplyds consist of a central protostar surrounded by a disk of dust and gas in which planets form. Several protostellar jets, outflows and nascent stars embedded in dust are scattered throughout the images.
“We have never been able to see the intricate fine details of how interstellar matter is structured in these environments, and to figure out how planetary systems can form in the presence of this harsh radiation. These images reveal the heritage of the interstellar medium in planetary systems,” said Habart.
Analogue evolution
Long considered an environment similar to the cradle of the solar system (when it formed more than 4.5 billion years ago), scientists today are interested in observing the Orion Nebula to understand, by analogy, what happened during the first million years of our planetary evolution.
The hearts of stellar nurseries like the Orion Nebula are obscured by large amounts of stardust making it impossible to study what is happening inside them in visible light with telescopes like the Hubble Space Telescope. Webb detects the infrared light of the cosmos, which allows observers to see through these layers of dust while revealing the action happening deep inside the Nebula.
Orion Nebula: JWST versus Hubble Space Telescope (HST)
The inner region of the Orion Nebula as seen by both the Hubble Space Telescope (left) and the James Webb Space Telescope (right). The HST image is dominated by emission from hot ionized gas, highlighting the side of the Orion Bar that is facing the Trapezium Cluster (off the top right of the image). The JWST image also shows the cooler molecular material that is slightly further away from the Trapezium Cluster (compare the location of the Orion Bar relative to the bright star θ2 Orionis A for example). Webb’s sensitive infrared vision can furthermore peer through thick dust layers and see fainter stars, allowing scientists to study what is happening deep inside the nebula.
Credit: NASA, ESA, CSA, PDRs4All ERS Team; image processing Olivier Berné.
Credit for the HST image: NASA/STScI/Rice Univ./C.O’Dell et al. – Program ID: PRC95-45a. Technical details: The HST image used WFPC2 mosaic.This composite image uses [OIII] (blue), ionized hydrogen (green), and [NII] (red).
“Observing the Orion Nebula was a challenge because it is very bright for Webb’s unprecedented sensitive instruments. But Webb is incredible, Webb can observe distant and faint galaxies, as well as Jupiter and Orion, which are some of the brightest sources in the infrared sky,” said Berné.
At the heart of the Orion Nebula is the ‘trapezium cluster’ of young massive stars whose intense ultraviolet radiation shapes the cloud of dust and gas. Understanding how this intense radiation impacts their surroundings is a key question in understanding the formation of stellar systems like our own solar system.
“Seeing these first images of the Orion Nebula is just the beginning. The PDRs4All team is working hard to analyze the Orion data and we expect new discoveries about these early phases of the formation of stellar systems,” said Habart. “We are excited to be part of Webb’s journey of discoveries.”
Webb is the most powerful space telescope in human history. Developed in partnership with NASA, the European Space Agency and the Canadian Space Agency (CSA), it boasts an iconic 6.5-metre-wide mirror, consisting of a honeycomb-like pattern of 18 hexagonal, gold-coated mirror segments and a five-layer, diamond-shaped sunshield the size of a tennis court. As a partner, CSA receives a guaranteed share of Webb’s observation time, making Canadian scientists some of the first to study data collected by the most advanced space telescope ever built.
Orion Nebula: JWST versus the Spitzer Space Telescope
The inner region of the Orion Nebula as seen by both the Spitzer Space Telescope (left) and the James Webb Space Telescope (right). Both images were recorded with a filter that is particularly sensitive to the emission from hydrocarbon dust that glows throughout the entire image. This comparison strikingly illustrates how incredibly sharp Webb’s images are in comparison with its infrared precursor, the Spitzer Space Telescope. This is immediately clear from the intricate filaments, but Webb’s sharp eyes also allow us to better distinguish stars from globules and protoplanetary disks.
Credit: NASA, ESA, CSA, PDRs4All ERS Team; image processing Olivier Berné.
Credit for the Spitzer image: NASA/JPL-Caltech/T. Megeath (University of Toledo, Ohio)
Technical details: The Spitzer image shows infrared light at 3.6 microns captured by Spitzer’s infrared array camera (IRAC). The JWST image shows infrared light at 3.35 microns captured by JWST NIRCam. Black pixels are artifacts due to saturation of the detectors by bright stars.
