The Hubble Space Telescope may have spotted the most distant star ever seen, thanks to a quirk of gravity. The Universe was only 900 million years old when the star is 13 billion light years away.
The farthest star seen by humans is this one.
Really?
The object is very far away and is very likely to mark a distance record that won't be broken for a while.
The star was located in the constellation of Cetus in a cluster of galaxies. It has a total mass of 900 trillion times that of the Sun, enough to make a thousand galaxies like the Milky Way.
Over a third of the way across the observable Universe is where WHL 0137-08 is located. There is a lot of real estate on the other side of it. The Universe helps us out by helping us out with the gravity of a cluster of galaxies. The distortion can cause images of objects to be duplicated so we can see more than one of them, it can warp the shape, and it can amplify the brightness of the more distant object. This effect is similar to how a lens behaves.
On the other side of the cluster is a previously unnamed galaxy called WHL 0137-zD1. The Sunrise Arc is the name of the long arcs that have been created by the lensing. There are several brighter blobs, probably in reality multiple images of just two different clusters of stars.
The real payoff is that along the way there is a single image of an object, what looks to be a lone star. The universe is only 13 billion years old, so we can see the same universe as it was when it was 900 million years old. It is really far away.
Seeing a single star is a stroke of luck. When the lensing mass is a lumpy distribution of galaxies like a cluster, it's complicated. There are peaks of magnification called critical curves, where technically the brightness magnification can be infinite, but in reality it is finite and can still be very large. One of the curves passes very close to the star, and while it can be measured with precision, the brightness magnification we see for the star is somewhere between a factor of 1,400 and 8,400! The magnification could be as much as 40,000 times.
This star is not visible because of that. Without this extra kick to the star's brightness, it would be too faint to see with Hubble. It's faint.
The models show that it is a massive star, at least 50 times the mass of the Sun, and possibly more. The stars are 100,000 times brighter than the Sun.
Earendel is the Old English word for rising light and is appropriate for a galaxy.
Is it a star? Is it a single star?
A star cluster at that extreme distance can be mistaken for a star. The source of the images is small, so it's not likely that this is a star cluster.
They can't exclude the possibility that this is a multiple system. Multiple systems tend to have one star that surpasses the others. Even if it is two stars, we are seeing two stars that are over 12 billion light years away. That is still amazing.
Several stars have been seen this way via cluster gravitational lensing, like one called LS1 in a galaxy 9 billion light-years from Earth. That record was destroyed by this one.
Stars were new at this time in the Universe. The first stars may have been born 300 million years after the Big bang, which is called a Cosmic dawn. This star is part of the earliest generations of stars. Even if we find stars more distant than this one, they won't be too far away. They can't be. They are not much farther away. The Universe was too young to make them.
How can this be confirmed? A set of James Webb Space Telescope observations have been approved by the astronomer. The idea that this is a single star, as well as refine our understanding of its characteristics and those of the star clusters seen along the Sunrise Arc, should be confirmed by images and spectra. We may know for sure in a year. Maybe less.
Stay informed. It will be setting records right out of the gate if it can confirm this. An excellent journal paper title will be made by the most distant star.
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