A cosmic occurrence that amplifies faraway celestial objects allowed a space telescope to witness a star from when the universe was merely 900 million years old. NASA’s Hubble observatory identified this star in 2022, marking it as the most distant and earliest star ever detected. Astronomers referred to it as Earendel, translating to “morning star” in Old English.

One year later, researchers employed the James Webb Space Telescope for additional investigation owing to its larger mirror and capability to gather light at extended infrared wavelengths. They hypothesized that they may have pinpointed a companion star, which was unexpected given Webb’s features.

A recent paper indicates that the distant light from Earendel might come from more than just one star or pair. Published in The Astrophysical Journal Letters, the research utilizes computer models to assess Webb telescope data, suggesting that Earendel could be a cluster of stars made up of several stars.

“My secret hope is that it is an individual star,” expressed Massimo Pascale, who spearheaded the research at UC Berkeley.

Researchers are eager to examine stars as ancient as Earendel to unlock secrets of the 13.8-billion-year-old universe. Hubble discovered Earendel through gravitational lensing, a phenomenon where a galaxy cluster intensifies and bends light. NASA compares this to a bowling ball on a trampoline, with the ball symbolizing a massive cosmic entity and the trampoline representing spacetime. Light curves and distorts as it traverses this warped spacetime, similar to incorporating a strong lens into a telescope.

Gravitational lensing can also replicate or elongate objects, akin to a funhouse mirror. The galaxy cluster WHL0137-08 functions as a magnifying glass, bringing Earendel’s distant galaxy, the Sunrise Arc, into view for Hubble, as it was 12.9 billion years ago. Due to cosmic expansion, the Sunrise Arc is now estimated to sit 28 billion light-years away.

Astronomers have familiarity with recognizing gravitational lensing effects, though this wasn’t always the scenario. In 1987, a large blue arc was initially presumed to be a colossal cosmic body but was later clarified as an optical illusion produced by a galaxy cluster. The New York Times covered this “bizarre” consequence of Einstein’s General Theory of Relativity.

Some astronomers question whether Earendel truly is a star. Pascale, currently an Einstein Fellow at UCLA, and his team reevaluated its size, factoring in mini halos of dark matter that could influence magnification. Considering these elements, Earendel’s dimensions might correspond with a star cluster.

Researchers contrasted Earendel with a recognized star cluster in the same galaxy, designated 1b. They observed resemblances: both are 30 to 150 million years old, lack heavy elements, and resemble ancient star clusters.

While 1b aligns well with star cluster models, so does Earendel, as per the study.

“For Earendel to be a solitary star or a binary, the alignment with the foreground galaxy cluster would have to be remarkably fortunate,” Pascale remarked. “If it’s a star cluster, the alignment doesn’t require such precision.”

The research does not hypothesize about the number of stars in the cluster, but Pascale posits that its mass could equate to hundreds of thousands of suns. Observing flickers could help ascertain if Earendel is a singular star, as a star cluster wouldn’t exhibit such variations.

Although the telescope time for this investigation is expensive, Pascale believes it could prove beneficial. Colleagues are receptive to the star cluster theory, but Pascale notes the paper does not conclusively establish it. He hopes the study aids in the ongoing discourse.

“Perhaps everyone keeps their opinions private,” he stated, “but most are open to the star cluster hypothesis.”