Astronomers just captured the sharpest view of a distant star ever seen

• Sharper views from a single telescope: Normally, astronomers link multiple telescopes together to get the clearest images of distant stars and galaxies. A UCLA-led team has now achieved record-breaking detail of the star beta Canis Minoris using just one telescope equipped with a breakthrough device called a photonic lantern.
• How it works: The photonic lantern divides starlight into many fine channels that capture subtle spatial patterns. Advanced computational techniques then combine these channels to rebuild a high-resolution image filled with details that would otherwise be lost.
• A new frontier for astronomy: This innovative approach could let scientists explore objects that are smaller, fainter, and farther away than ever before, offering fresh insight into the hidden structure of the universe and sparking new discoveries.

A Breakthrough View From a Single Telescope

For the first time, astronomers have used a new imaging method on a ground-based telescope to capture the most detailed look ever at the disk surrounding a distant star. Led by UCLA researchers, the achievement revealed hidden structures that had never been seen before. This breakthrough paves the way for scientists to study finer details of stars, planets, and other celestial objects, potentially transforming how we explore the universe.

A telescope's ability to reveal faint or distant objects depends on its size. Larger telescopes can collect more light, allowing them to see dimmer targets and produce sharper images. The highest levels of detail are usually reached by linking multiple telescopes together to form an array. Building these large instruments, or connecting them, has long been the key to achieving the precision needed for discovering new cosmic features.

Harnessing Light With a Photonic Lantern

Using a device called a photonic lantern, astronomers can now make better use of the light gathered by a telescope to produce extremely high-resolution images. The details of this breakthrough appear in Astrophysical Journal Letters.

"In astronomy, the sharpest image details are usually obtained by linking telescopes together. But we did it with a single telescope by feeding its light into a specially designed optical fiber, called a photonic lantern. This device splits the starlight according to its patterns of fluctuation, keeping subtle details that are otherwise lost. By reassembling the measurements of the outputs, we could reconstruct a very high-resolution image of a disk around a nearby star," said first author and UCLA doctoral candidate Yoo Jung Kim.

The photonic lantern divides the incoming light into multiple channels based on how the light wavefront is shaped, much like separating the notes of a musical chord. It also divides light by color, creating a rainbow-like spectrum. The device was designed and built by the University of Sydney and the University of Central Florida, and it forms part of the instrument FIRST-PL, developed and led by the Paris Observatory and the University of Hawai'i. This system is installed on the Subaru Coronagraphic Extreme Adaptive Optics instrument at the Subaru Telescope in Hawai'i, which is operated by the National Astronomical Observatory of Japan.

"What excites me most is that this instrument blends cutting-edge photonics with the precision engineering done here in Hawai'i," said Sebastien Vievard, a faculty member in the Space Science and Engineering Initiative at the University of Hawai'i who helped lead the build. "It shows how collaboration across the world, and across disciplines, can literally change the way we see the cosmos."

Pushing Beyond Traditional Imaging Limits

This method of separating and analyzing light enables a new way to see fine detail, achieving sharper resolution than traditional telescope cameras.

"For any telescope of a given size, the wave nature of light limits the fineness of the detail that you can observe with traditional imaging cameras. This is called the diffraction limit, and our team has been working to use a photonic lantern to advance what is achievable at this frontier," said UCLA professor of physics and astronomy Michael Fitzgerald.

"This work demonstrates the potential of photonic technologies to enable new kinds of measurement in astronomy," said Nemanja Jovanovic, a co-leader of the study at the California Institute of Technology. "We are just getting started. The possibilities are truly exciting."

At first, the researchers faced a major challenge: turbulence in Earth's atmosphere. The same shimmering effect that makes distant horizons appear wavy on a hot day causes starlight to flicker and distort as it travels through the air. To correct for this, the Subaru Telescope team used adaptive optics, a technology that continuously adjusts to cancel out these distortions and stabilize the light waves in real time.

"We need a very stable environment to measure and recover spatial information using this fiber," said Kim. "Even with adaptive optics, the photonic lantern was so sensitive to the wavefront fluctuations that I had to develop a new data processing technique to filter out the remaining atmospheric turbulence."

Exploring Beta Canis Minoris in Stunning Detail

The team put their technique to the test by observing the star beta Canis Minoris (β CMi), located about 162 light-years away in the constellation Canis Minor. This star is surrounded by a fast-spinning hydrogen disk. As the gas in the disk moves, the side rotating toward Earth appears bluer, while the side moving away looks redder, a result of the Doppler effect (the same phenomenon that changes the pitch of a moving car's sound). These color shifts slightly alter the apparent position of the starlight depending on its wavelength.

By applying new computational methods, the researchers measured these color-based position shifts with about five times more precision than ever before. In addition to confirming the rotation of the disk, they discovered that it is lopsided.

"We were not expecting to detect an asymmetry like this, and it will be a task for the astrophysicists modeling these systems to explain its presence," said Kim.

A New Way to See the Universe

This innovative approach will allow astronomers to observe smaller and more distant objects with unprecedented clarity. It may help solve long-standing cosmic mysteries and, as in the case of the lopsided disk around β CMi, uncover entirely new ones.

The project involved an international collaboration that included scientists from the Space Science and Engineering Initiative at the University of Hawai'i, the National Astronomical Observatory of Japan, the California Institute of Technology, the University of Arizona, the Astrobiology Center in Japan, the Paris Observatory, the University of Central Florida, the University of Sydney, and the University of California Santa Cruz.