Happy Nice Mall

Starlight, star bright, how far you seem tonight.

Astronomers announced Wednesday the discovery of the most distant and oldest star ever seen, a point of light that shines 12.9 billion years ago, or just 900 million years after the Big Bang that gave birth to the universe.

This means that the light from the star travels 12.9 billion light-years to reach Earth.

The finding was part of the effort used. Hubble space telescope to search for some of the farthest and oldest galaxies in the universe. By lucky coincidence, astronomers were able to distinguish a single star system in one of these galaxies.

“It was an unexpected surprise to find something this small,” said Brian Welch, a graduate student at Johns Hopkins University in Baltimore. A paper describing the discovery, published Wednesday in the journal Nature.

Often distant objects are too dim to see. However Einstein’s general theory of relativityprovides a useful workaround, explaining how gravity bends space. A massive cluster of galaxies very close to us can act as a lens to amplify light from the much more distant stars and galaxies behind it.

A survey using the Hubble Space Telescope examines 41 galaxy clusters. “When you look at a group of really massive galaxy clusters, you’re likely to find some really magnified objects behind them,” said Mr. Welch.

Mr. Welch said the galaxy cluster typically magnifies the brightness of the object behind it by up to 10 times.

But the light is not magnified evenly. Ripples in space-time can create bright spots, just as ripples on the surface of a swimming pool create patterns of bright spots at the bottom of the pool. When examining one of the magnified distant galaxies, astronomers found that there was a point of light lined up with one of the waves, and its brightness was magnified a thousand times or more.

“The galaxy is somehow stretching into this long crescent-shaped arc,” said Mr. Welch. “And then the star is just one component of it.”

Because the universe is expanding, objects farther away are moving away faster. This shifts the frequency of the light towards longer wavelengths. The star detected by Mr. Welch and colleagues has what astronomers call a redshift of 6.2, far higher than the previous record holder for the farthest single star. Reported in 2018, this star had a redshift of 1.5, corresponding to when the universe was about four billion years old.

Researchers nicknamed the new star Earendel – Old English “morning star.” If it’s a single star, astronomers estimate it’s massive—about 50 times the mass of our sun. There may also be a system of two or more stars.

It will take years for Earendel and galaxy cluster to align, so Earendel will be one of the targets in the first year of newly launched observations. James Webb Space TelescopeIt has a larger mirror than Hubble and collects light at longer infrared wavelengths.

Webb observations will be able to measure luminosity across a wavelength spectrum. This will help astronomers determine the star’s temperature. “We need this spectrum to tell with some kind of absolute certainty that it’s a star as opposed to another kind of object,” said Mr. Welch.

Mr. Welch said more detailed observations by Webb could identify Earendel’s composition. The Big Bang produced only the lightest elements, such as hydrogen and helium. Therefore, the oldest stars are expected to contain lower concentrations of heavier elements created by fusion reactions in stars and explosions of dying stars. The current hypothesis is that with less heavy elements, most early stars must have been massive and bright.

“It looks pretty hot and pretty big,” said Steven Finkelstein, an astronomer at the University of Texas at Austin who was not involved in the research.

Yet this star alone would not be enough to prove the case of larger stars in the early universe. “But it definitely supports that,” said Dr. Finkelstein. “If you start creating large numbers of them, and many of them seem quite large, the evidence will become stronger that larger stars are the norm in the distant universe.”

The Webb telescope should also be able to find other distant magnified stars such as Earendel, though it remains to be seen how many of them are lined up randomly with a gravitational lens. It can even detect some stars at a redshift of 10 to 20, which corresponds to 100 million to 500 million years after the Big Bang.

Dr. “This is right in the middle of the window where we think the first stars formed,” Finkelstein said.