Earlier this year, the Hubble Space Telescope had discovered the star that is so far farthest from Earth in the Universe. Now the brand new telescope James Webb Space Telescope could see it.
The star in question was named Earendelwhich is the name of a character in the prologue “The Silmarillion” Artwork “Lord of the Rings” by JRR Tolkien. It was discovered by Hubble thanks to a gravitational lens phenomenon. Earendel is at a distance of 12.9 billion light-years from Earth and its light is very weak. On Tuesday August 2, the astronomers behind the Twitter account Cosmic Spring JWST announced that the star appeared in an image captured by the Webb Telescope.
In the tweet, the astronomers say they’re excited to share the first image of Earendel captured by the Webb Telescope. According to them, the sightings that led to the image were made on Saturday, July 30, 2022.
The phenomenon of gravitational lensing
To be able to detect the most distant stars or galaxies, astronomers are often helped by the phenomenon of gravitational lens. This phenomenon is based on the fact that very massive objects such as galaxies or black holes bend the light from other objects behind them.
When light passes near such a super-massive object, it behaves as if it passed through a telescope lens. The resulting image is enlarged, but it is also distorted. In any case, with this phenomenon, we can somehow extend the reach of telescopes like Hubble and Webb.
The Webb Telescope
In the case of the Webb telescope, this space observatory was designed to observe the first galaxies of the early Universei.e. the galaxies of the first hundreds of millions of years following the dark period after the big Bang. However, astronomers believe that it will not be possible to observe individual stars from this first generation of stars. But thanks to the phenomenon of gravitational lensing, we could still see in detail the interior of these first stellar groupings.
According to astronomers from Space Telescope Science Institute in Maryland, which manage Hubble and Webb, the latter was developed to study the first stars. Until recently, they thought it meant star populations in early galaxies. However, in the past three years, three individual stars greatly magnified by gravitational lensing have been discovered. The researchers thus indicate that this phenomenon could make it possible to observe individual stars at cosmological distances using the Webb telescope.