Size matters to telescope image resolution. The larger the viewing hole, the more light it can collect. More light helps reveal weaker ones space objectsand also improve the sharpness of the images themselves.
For astronomers, the best results are usually achieved by sharing images between telescopes around the world that are linked to each other. However, researchers from the University of California, Los Angeles (UCLA) and the National Astronomical Observatory of Japan have demonstrated that such a network approach is not always necessary. They needed just one telescope to get the sharpest look in history at the deep red disk of hydrogen-alpha spectral light from a distant star. As they explain in their study recently published in Letters in an astrophysical journalThis achievement relied on a finely tuned optical fiber called a photonic flashlight.
In traditional cameras they diffraction limit (or the maximum amount of detail it can capture) is hampered by the wave nature of light. A photon flashlight bypasses these waves by first separating the light into individual wavelength forms. The team said the process is similar to dividing a single musical chord into notes. The astronomers then used a photon flashlight to further separate these light wavefronts into colors, like rainbow.
“This device separates starlight according to its vibrational patterns, preserving fine details that are otherwise lost,” study co-author Yoo Jung Kim. says the statement. “By collecting these measurements, we were able to reconstruct a very high-resolution image of the disk around the nearest star.”
Kim and her teammates were initially disturbed by visual noise coming from the Earth's atmosphere. Just as a hot sunny day can make the horizon appear wavy, their telescope continued to image objects as if they were swaying. The first step in the solution was adaptive optics. This process continually neutralizes the atmospheric turbulence that causes these waves in real time. However, the team soon realized that they needed additional tools.
“Even with adaptive optics, the photon flashlight was so sensitive to wavefront fluctuations that I had to develop a new data processing technique to filter out the remaining atmospheric turbulence,” Kim said.
Using this filter, the team took an unprecedented look at a star in the constellation Canis Minor called beta Canis Minor (βCMi). Located approximately 162 light-years from Earth, β CMi is surrounded by an incredibly fast-moving disk of hydrogen. Because of Doppler effectFast gas approaching Earth glows blue, while gas moving away glows red. Thus, the color shift causes the position of the visible light of the star system to change depending on the wavelength.
Using their new technique, astronomers measured changes in the star's image as a function of color with an accuracy five times greater than previous observations. At the same time, they also discovered something unexpected: the star's disk was skewed. It's now up to another research department to figure out why that is, Kim said.
“We didn't expect to find this kind of asymmetry,” she said. “Astrophysicists modeling these systems will have to explain its presence.”
