Detailed images of nebulae at the bottom of the ship are a matter of wonder
The underside nebula is a thick cloud of dust and gas in which stars are actively being conceived. Astronomers have acquired the highest resolution near-infrared images of the ship's underside nebula to date.
Illustration: The latest image of the ship's underside nebula.
The images, recently observed by the Gemini South Telescope in Chile, amaze viewers. These images can also help understand the stellar nursery and the process of star birth, and in part predict what images will be brought when the James Webb Space Telescope finally lifts off.
Illustration: Gemini South Telescope in Chile. The source of the figure is bingimage
Patrick Hattigen, a physicist and astronomer at Rice University in the United States, said, "The results of the images are very impressive. ”
Illustration: Patrick Hattigen, professor of physics and astronomy at Rice University.
"At the edge of the nebula you can see a large amount of detail that has never been observed before, including a long series of parallel ridges that may be generated by a magnetic field, almost smooth sine waves and top debris, as if peeling out of the nebula by strong winds."
The process of star birth is fascinating, but it doesn't happen everywhere— it requires thick gas and dust clumps, hydrogen molecules are abundant and dense, and some areas collapse by gravity due to their own weight.
When these knots collapse, their rotation is enhanced due to conservation of angular dynamics, producing a spinning disk of material that forms protostars (and possibly planets as stars form). ）
Illustration: Protostars.
Therefore, the most suitable place for star formation is the place where it is densest and dustiest. Nebulae between stars appear translucent, and among the flickering stars, their wavelengths of light resemble a dark vacuum, making it a huge flaw for the Hubble Space Telescope.
"Hubble can observe optical and ultraviolet wavelengths that are blocked by dust in this star-forming region," Hattigen said. ”
Illustration: Hubble Space Telescope.
But infrared and near-infrared wavelengths can pass through thick layers of stardust, allowing astronomers to see these enigmatic nebulae, which is where observational instruments like Gemini South are superior to Hubble. But both are deficient, hubble is in space, and Gemini is south of Earth, wrapped in Earth's atmosphere.
Atmospheric turbulence distorts and separates distant light, which is why stars seem to flicker when we look up into the night sky. This is a difficult problem for ground-based astronomy, and many methods have been tried to correct it over the years.
In the past, when observations were complete, this distortion effect was eliminated when processing the image. However, with the advancement of science and technology, we have been able to use so-called adaptive optics to correct atmospheric turbulence during observation.
The South Gemini Adaptive Optical Imager contains five lasers that shoot into the sky to project an artificial "guide star" that corrects for atmospheric turbulence effects by measuring the guide star.
Illustration: Gemini South Adaptive Optical Imager.
Hattigen and his team used this technique to obtain the latest ship-bottom nebula images at a resolution ten times higher than images captured without adaptive optics, and at this wavelength it is twice as sharp as the Hubble images. The images show a whole new level of detail about how dust and gas interact, and can also see a cascade of large, young stars nearby.
This part of the nebula is called the "Western Wall," and the radiation from the explosion of the hot nova ionizes hydrogen, causing the nova to emit infrared light. The ultraviolet radiation of these stars also gasifies the outer layer of hydrogen.
Using different filters, the team was able to obtain different images of hydrogen on the surface of the nebula and of evaporated hydrogen.
"This area is probably the best example of a radiation interface sky, and the new images are much clearer than we've seen before, providing the clearest view to date of how large novae affect their surfaces and how stars and planets form," Hardigan said. ”
The James Webb Space Telescope launched about a year later (good luck) to observe infrared and near-infrared; so the researchers say these images of the ship's underside nebula are also a bit like what we'll see with the James Webb telescope in the future.
But it also reveals the power of adaptive optics to complement and refine observational capabilities.
"Structures like the Western Wall will be huge hunting grounds for future adaptive-optic ground-based telescopes like the Weber telescope and Gemini South, both of which can penetrate the dust envelope and reveal new information about the birth of stars," Hadigen said. ”
Author: Michael Starr
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