Researchers Record First Radio Depictions of Annular Solar Eclipse’s “Ring of Fire”

Upper Section: Radio portrayals of the October 14, 2023, solar eclipse, as observed by the Long Wavelength Array at Owens Valley Radio Observatory. Lower Section: Diagrammatic illustrations of what the eclipse appeared to be in visible light at that moment. Credit: Sijie Yu

Utilizing the cutting-edge Long Wavelength Array at Owens Valley Radio Observatory, investigators have obtained revolutionary radio depictions of the “ring of fire” phenomenon during a solar eclipse. This technology heralds notable strides in the field of solar observation.

A team from the New Jersey Institute of Technology’s Center for Solar-Terrestrial Research (NJIT-CSTR) recorded the solar eclipse on October 14 in an unprecedented manner, capturing the first-ever radio portrayals of the well-known “ring of fire” effect of an annular eclipse.

While the eclipse was partially discernible across much of the continental United States for several hours on that Saturday, the complete “ring of fire” effect was observable for less than five minutes and exclusively within its 125-mile-wide path of annularity.

Nevertheless, these fresh radio observations — substantially longer in duration than the recent partial eclipse witnessed by millions — offer remarkable depictions of the ring phenomenon, lasting for more than an hour.

OVRO-LWA: A Milestone in Solar Observational Technology

The researchers employed the newly operational Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA), located in Owens Valley, California, to capture groundbreaking images of radio emissions originating from the Sun’s extended corona while the moon traversed between the Earth and the Sun.

Dale Gary, distinguished professor of physics at NJIT-CSTR and a co-investigator on the OVRO-LWA initiative, which is financially supported by the National Science Foundation, stated, “The radio imaging quality of the Sun that we observed in this ‘ring of fire’ eclipse is unparalleled.”

Observations from the Owens Valley Radio Observatory – Long Wavelength Array (OVRO-LWA) showed the October 14 solar eclipse nearing its maximum obscuration. The radio sun’s appearance occasionally fluctuates due to ionospheric refraction, an effect similar to watching the sun under a water surface exhibiting ripples. Such distortions were particularly noticeable during the early stages of the video recording. Credit: Sijie Yu.

The team noted that although their observation site in California was not situated within the belt of the annular eclipse, the radio emissions provided a clearer and more expansive view of the solar disk, thanks to their sensitivity to the Sun’s extended corona. Bin Chen, associate professor of physics at NJIT-CSTR who led data processing efforts, said this offered a unique scientific opportunity to study the Sun’s extended corona with unparalleled resolution at these wavelengths.

Technical Overview and Prospective Research Plans

Directed by Gregg Hallinan at the California Institute of Technology (Caltech), OVRO-LWA comprises 352 antennas that collect data across radio wavelengths ranging from approximately 20 to 88 MHz. It provides the most detailed images of the radio Sun in this frequency range, the size of which is approximately double that of the visible solar disk.

Hallinan commented that documenting this remarkable event was an excellent opportunity to showcase OVRO-LWA as a novel radio observatory capable of studying not just the Sun, but also other celestial phenomena like exoplanets, cosmic rays, and the early universe.

The next annular solar eclipse will be visible from South America in October 2024. However, those in the United States will have to wait until June 2039 for the next domestic ‘ring of fire’ eclipse. Nevertheless, a total eclipse will be observable across the central U.S. as early as April 8 of next year.

According to the research team, this recent event stands as an exceptional example of initial observations made with this new instrument. OVRO-LWA’s newly acquired capabilities are expected to significantly contribute to the field, especially as the current 11-year solar cycle reaches its zenith in 2025.

Bin Chen added, “We are in the process of developing an automated data processing pipeline that will soon yield near-real-time images of the Sun and make them publicly accessible. These images from the eclipse serve as a validation for our upcoming endeavors, which will create unprecedented opportunities for advancements in solar astronomy and space weather studies.”

Frequently Asked Questions (FAQs) about Annular Solar Eclipse Radio Observations

More about Annular Solar Eclipse Radio Observations

• Owens Valley Radio Observatory (OVRO)
• New Jersey Institute of Technology’s Center for Solar-Terrestrial Research (NJIT-CSTR)
• National Science Foundation
• Annular Solar Eclipses
• Solar Corona Observations
• Radio Astronomy
• Upcoming Solar Eclipses
• California Institute of Technology (Caltech)
• Solar Astronomy
• Space Weather Studies