The most distant star ever known formed less than a billion years after the universe was born from the Big Bang and could reveal a lot about the early universe.
Earendel’s position in this Hubble image. Photo: NASA
Scientists named the star “Earendel” – the Old English word for “morning star”. Earendel, number WHL0137-LS, is at least 50 times more massive than the Sun and millions of times more luminous. Discovered by NASA’s Hubble space telescope, this star is so distant that its light takes 12.9 billion years to reach Earth. The star was born when the universe was about 900 million years old, 7% of its present age. Previously, the most distant star detected by the Hubble telescope in 2018 existed when the universe was about 4 billion years old, or 30% of today’s age.
According to study leader Brian Welch, an astrophysicist at Johns Hopkins University in Baltimore, the discovery offers an opportunity to study in detail a star in the early universe. Normally, even a bright star like Earendel cannot be observed from Earth at such a great distance. The smallest object ever observed at a similar distance is a star cluster located inside the first galaxies.
Scientists discovered Earendel with the help of the massive galaxy cluster WHL0137-08 located between Earth and the star. The cluster’s gravity distorts the field of space and time, resulting in a natural magnifying lens that enhances light from distant objects lying behind the galaxy like Earendel. This gravitational lens distorts light from the galaxy containing Earendel, forming a long crescent that the team calls the Sunrise Arc. The way Earendel aligns with WHL0137-08 means that the star appears to be at the extreme near a curve in the space-time field, creating a maximum luminosity that makes Earendel stand out from the halo from its own galaxy.
Welch emphasized that this is not the most distant object that researchers have ever found. “Hubble has observed galaxies at greater distances. However, we see light from their millions of stars mixing together. This is the furthest object from which we can identify light. From an individual star We see the star 12.8 billion years ago, but that doesn’t mean the star is 12.8 billion years old. Instead, it could be only a few million years old and not never reached such an age,” Welch explained.
Given the star’s mass, it is almost impossible to survive today, as the larger the star, the faster it tends to burn fuel and explode, or rapidly collapse into a black hole. The oldest stars known to researchers also formed around the same time but were much lighter, so they continue to shine to this day.
Researchers don’t know much about Earendel, such as the exact mass, luminosity, temperature, and type of star. They don’t even know if it’s a star or binary. Most large stars the size of Earendel are surrounded by a fainter smaller star, and Earendel’s light obscures its companion. The team will continue to observe with NASA’s James Webb space telescope to analyze Earendel’s infrared light and identify many of its features. They published their findings on April 20 in the journal Nature.
An Khang (According to Space)
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