Earendel Likely a Star Cluster

New analysis questions whether Earendel is a single star and suggests it could be a compact star cluster seen through gravitational lensing.

Earendel Likely a Star Cluster Instead of Lone Star

Earendel was spotted in 2022 by the Hubble Space Telescope thanks to a gravitational lens created by the foreground galaxy cluster WHL0137-08. The light traveled about 28 billion years to reach us, with the emission dating to roughly 13 billion years ago. Early readings suggested a solitary star about 50 times the Sun’s mass, possibly part of a binary system. The discovery relied on the Sunrise Arc, a stretched image of a distant galaxy produced by lensing, and follow‑up data from the James Webb Space Telescope added more detail. A new study uses stellar population modeling to reassess what Earendel might be.

The latest paper compares Earendel to nearby features in the same arc and tests whether the observed spectrum fits a simple stellar population model. The authors report that Earendel’s spectrum and the arc’s features are consistent with metal‑poor populations and that the fits stay strong across several stellar population libraries. They conclude Earendel is best described as a star cluster rather than a single star, though a binary origin isn’t completely ruled out. The interpretation sits with expectations for what the first star‑forming regions may have looked like and aligns Earendel with early globular cluster formation rather than a lone behemoth.

This update shows how science evolves with better data. Gravitational lensing opens a window into the past, but it also complicates what we are really seeing. If Earendel is a star cluster, the finding still teaches us about star formation in the universe’s first billion years and the kinds of structures that could survive to later eras. The result also underscores the cautious pace of astronomy, where new models must be tested against multiple observations before a firm label is assigned. In short, the cosmos keeps reshaping its own story as data improves.

Highlights

As telescopes sharpen, Earendel will continue to challenge and refine our picture of the early cosmos.