The researchers called the new star Earendel – in Old English the “morning star”. If it’s a single star, astronomers estimate it’s a massive star — about 50 times the mass of our sun. It can also be a two or more star system.
The alignment of the Earendel and the galaxy group will continue for years, so Earendel will be one of the targets during the first year of observations by the group’s newly launched James Webb Space Telescope, which has a mirror larger than Hubble and collects light at longer infrared wavelengths.
Webb’s observations will be able to measure brightness across a spectrum of wavelengths. This will help astronomers determine the temperature of the star. “We really need that spectrum to say with some kind of absolute certainty that this is a star compared to another kind of thing,” Mr. Welch said.
Mr. Welch said that later, more detailed observations by Webb could determine Earendel’s composition. The Big Bang produced only the lightest elements, such as hydrogen and helium. The first stars are thus expected to contain lower concentrations of heavier elements, which arise from fusion reactions within stars and in the explosions of dying stars. The current hypothesis is that with fewer heavier elements, the first stars should be large and bright.
“It looks very hot and very massive,” Stephen Finkelstein, an astronomer at the University of Texas at Austin who was not involved in the research, said of Earndale.
However, this star alone would not be enough to prove the state of the largest stars in the early universe. “But he definitely supports that,” Dr. Finkelstein said. “If you start making a large number, and many of them appear to be very massive, the evidence will get stronger and stronger that more massive stars are the norm in the distant universe.”