The Sunrise Arc

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The Sunrise Arc is smeared across 15 seconds of arc, in the Constellation Cetus, by the gravitational lens that makes it visible.

The Sunrise Arc is the name of a small distant galaxy, first detected in 2016 by Dan Coe, of John Hopkins University.[1] The galaxy has an enormous red shift, because it lies 12.9 billion lightyears from Planet Earth, and the light we see from it was emitted when the Universe was only 900 million years old.

The galaxy was detected by the Reionization Lensing Cluster Survey (RELICS) Program. That program relies on gravitational lensing by distant galaxies to detect even more distant objects, objects magnified by those gravitational lenses, that would otherwise be too dim to be detectable.

Due to gravitational lensing by a supercluster of galaxies that lie between Planet Earth and The Sunrise Arc the light from that galaxy has been smeared across 15 seconds of arc.

In June of 2021 Brian Welch, a PhD student of Coe's, published a paper describing star cluster's within the galaxy that were surprisingly studiable, due to the lensing.[2]

On March 30, 2022, Welch and a team of colleagues announced their conclusion that, within the galaxy, they had found a bright blue supergiant Welch dubbed Earendel - the oldest and most distant star to ever be detected.[3]


  1. Joel Achenbach. Hubble telescope detects most distant star ever seen, near cosmic dawn, Washington Post, 2022-03-30. Retrieved on 2022-03-30. “Earendel is part of an early, small galaxy whose light has been magnified and distorted in two curved strips as a result of such lensing. Astronomer Dan Coe of Johns Hopkins discovered and named the Sunrise Arc in 2016 as part of a Hubble observation program. Welch, Coe’s student, scrutinized a tiny speck — some kind of object — providentially located on the arc where the magnification was highest. Over the course of 3½ years, the object remained in that spot.”
  2. Brian Welch. American Astronomical Society meeting #238, id. 324.09., Bulletin of the American Astronomical Society, June 2021. Retrieved on 2022-03-30. “I will present RELICS observations of the highly magnified Sunrise Arc, a 15" long lensed arc observed at z = 6.2.”
  3. Welch, Brian, et al. (2022-03-30). "A highly magnified star at redshift 6.2". Nature 603: 815-818. DOI:10.1038/s41586-022-04449-y. Retrieved on 2022-03-30. Research Blogging.