The James-Webb Telescope captures Orion’s star nursery

This time, its giant mirror, 6.5 meters in diameter, turned towards the Orion Nebula: the James-Webb space telescope of the American, European and Canadian agencies continues to dazzle astronomers and the public with the images that he sends from his observation post located more than 1.5 million kilometers from Earth.

On September 12, the PDRs4All program, co-directed by the French Olivier Berné (from the Astrophysics and Planetology Research Institute, in Toulouse) and Emilie Habart (from the Space Astrophysics Institute, in Paris-Saclay) and the Belgian Els Peeters (from the University of Western Ontario, Canada) has published never-before-seen details of Orion, the closest star nursery to us in our galaxy, about 1,350 light-years from Earth.

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In this region, stars are born inside the numerous filaments which structure the image and which move according to the stellar winds. The brown structure that bars the image and evokes the flight of an eagle with its “head” made of a shining star, is a front of matter made up of gas and dust. This area is on the boundary between a bluish side, where ultraviolet radiation from the star cluster at the center of the nebula ionizes hydrogen and pushes matter outward, and a region of dust, molecules of hydrocarbon which are resistant to radiation (rather in green on the image).

“Globes” and white spots

Circled in red, the star that forms the head of the eagle seems to create its own nebula around it, pushing matter to the periphery. “This glow, probably due to the diffusion of light on the dust, evokes that of certain sunsets”says Olivier Berné.

The nebula seen by Hubble (left) and James-Webb (right).
The nebula as seen by Spitzer (left) and James-Webb (right).

The team of astronomers also immediately noticed by zooming in countless “globules”small white spots in the nebula, in the shape of a jellyfish, a Venetian mask, a head, etc., which are protoplanetary disks, or “proplyds”, i.e. an accretion of matter around a young star , seat of the appearance of future planets. “The dimensions are only ten astronomical units, the size of our solar system. The James-Webb had never seen one before”testifies Olivier Berné, specialist in these regions, similar to those that our own solar system was at its birth.

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“We are satisfied. The details of the image give an incomparable three-dimensional vision », appreciates Emilie Habart. The differences with space telescopes Hubble (which observes the visible) or Spitzer (in the infrared) are indeed eloquent. James-Webb “sees” through the dust and locates stars that have remained hidden from Hubble until now. He also sees ten times sharper than Spitzer, which makes it possible to study in detail small objects such as protoplanetary disks or filaments of matter.

waterfalls of matter

A second “bonus” image was also presented, which shows an area a few light years further north from the previous one. The same dynamic phenomena are observed in these sorts of matter cascades: cold hydrocarbon matter (in green), heated hydrogen gas (in blue), and, in red, probably hot dust. Stars more or less young according to their color also illuminate the scene.

Northern region of M42, the Great Orion Nebula, observed with Detector A of NIRCam, the infrared camera of the James-Webb Space Telescope.

These images, in false colors, taken by the NIRCam instrument, James-Webb’s infrared camera, were produced by graphic designer Salomé Fuenmayor, who assembled fourteen shots of the telescope taken in several infrared filters, therefore invisible to the eye. naked. The colors correspond to the radiation of different compounds, but it is too early to precisely associate a color with specific chemical elements such as hydrogen, molecular hydrogen, hydrocarbons, dust…

For this, astronomers are waiting to receive and study other data from the same region, the exact composition, for almost every pixel in the image, of the light emitted in each wavelength (or color). This information is the only one that will make it possible to precisely identify the light sources, their composition, their temperature, their evolution… This will be the key to understanding the mysterious interaction of star radiation with the surrounding matter, but also the formation of new generations of stars. stars, or even the carbon cycle (with molecules that heat up, break up, cool down, etc.). In the line of sight, the writing of complete scenarios for the appearance of planetary systems like ours.

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