The Hubble Space Telescope has detected the most distant star that has been observed from Earth. The individual star is 9 billion light-years away from Earth.
Individual stars are more difficult to find compared to galaxies because their light is fainter.
An international team of researchers published a new study on the star in the journal Nature Astronomy. It was led by Patrick Kelly and included Masamune Oguri. This newly discovered star was named Icarus because the brightness was magnified 2,000 times by the gravity of a larger object in front of it.
Icarus was discovered to be 9 billion light-years away from Earth, which is close to the age of the universe at 13.8 billion years old. Stars are usually too difficult to be seen individually. Scientists are usually able to find galaxies and supernovas, which tend to be brighter in the sky.
Icarus is classified as an ordinary star, meaning that it is on the main sequence of evolution of stars, which fuses hydrogen into helium. When stars run out of hydrogen to burn, the stars are then off the main sequence. When larger stars get off the main sequence, they can explode into supernovas. Smaller stars can collapse into white dwarfs.
Researchers said that this star is at least 100 times farther away than the next individual star that can be studied.
How Icarus Was Discovered
Icarus was discovered while scientists were observing galaxy cluster MACS J1149+2223, which is 5 billion light-years away. While observing the cluster, they noted that there was a flickering light in the background. Closer observations of the flickering light source revealed that it was not a supernova as originally thought — but actually a blue star.
It was able to be seen because the galaxy cluster was able to bend space-time to make the star's image brighter. This is called gravitational lensing, which is when an object is magnified by the light of the object directly behind it.
This is the first time that an individual normal star has been observed at a distance of 9 billion light-years away. Scientists were also able to test and reject one theory regarding dark matter. They were able to determine that dark matter doesn't consist of a bunch of primordial black holes inside of galaxy clusters.