The Hubble Space Telescope discovered Earendel (WHL0137-LS) in 2022 at a comoving distance of 28 billion light-years, making it the most distant individual stellar object ever detected. Its light, emitted 900 million years after the Big Bang, carries a redshift z=6.2 and reached Earth after 12.9 billion years. The galaxy cluster WHL0137-08 gravitationally lenses Earendel, originally estimated to magnify its brightness 1,000–40,000 times, allowing Hubble to resolve it across four observation epochs between 2016 and 2019.

Follow-up imaging by the James Webb Space Telescope in 2022–2023 revealed a massive B-type star candidate with a-type star exceeding 13,000 K and roughly a million times the Sun's luminosity, plus hints of a cooler companion. JWST's NIRCam data initially supported the single-star interpretation, but spectroscopic fitting complicated the picture with a strong Balmer break and blue UV slope suggesting multiple components.

A 2025 study revised the magnification estimate dramatically downward to μ=43–67, arguing that sub-galactic dark matter halos perturb the lens model and relax the physical size constraint by up to tenfold. This aligns with spectroscopic evidence that Earendel is most likely a metal-poor globular cluster progenitor rather than a single star or binary system, though the latter is not fully excluded.