The find is a huge leap back in time from the previous one-star record holder. was discovered by Hubble in 2018. This star existed when the universe was about 4 billion years old, or 30 percent of its current age, at a time that astronomers refer to as the “red 1.5 shift.” Scientists use the word “redshift” because as the universe expands, light from distant objects stretches or “shifts” to longer, redder wavelengths as it travels toward us. The recently discovered star is so far away that it took 12.9 billion years for its light to reach Earth, giving us a glimpse of when the universe was just 7 percent of its current age, shifting to red 6.2. The smallest objects we have seen before at such a great distance are star clusters embedded in early galaxies. “We hardly believed it at first, it was much farther away than the previous farther, higher redshift star,” said astronomer Brian Welch of Johns Hopkins University in Baltimore, the lead author of the paper describing the discovery. published in the journal Nature on March 30. The discovery was made from data collected during Hubble’s RELICS (Reionization Lensing Cluster Survey) program, led by co-author Dan Coe at the Space Telescope Science Institute (STScI), also in Baltimore. “Normally at these distances, entire galaxies look like small smudges, with light from millions of stars mixing with each other,” Welch said. “The galaxy that hosts this star has been magnified and deformed by a gravitational lens into a long crescent that we called the east arc.” After studying the galaxy in detail, Welch found that one feature is an extremely large star named Earendel, which means “morning star” in Old English. The discovery promises the opening of an uncharted era of very early star formation. “Earendel existed so long ago that it may not have all the same raw materials as the stars around us today,” Welch explained. “Earendel’s study will be a window into an era of the universe that we are not familiar with, but that led to everything we know. It’s like reading a really interesting book, but we started with the second chapter and now we’ll have a chance to see “how it all started,” Welch said.
When the stars are aligned
The research team estimates that Earendel is at least 50 times the mass of our Sun and millions of times brighter, competing with the massive stars known. But even such a bright, very massive star would be impossible to see at such a great distance without the help of natural magnification from a huge cluster of galaxies, WHL0137-08, sitting between us and Arendel. The mass of the galaxy cluster distorts the fabric of space, creating a powerful natural magnifying glass that distorts and greatly amplifies light from distant objects behind it. Thanks to its rare alignment with the Galaxy Magnifying Glass, the Earendel star appears directly or very close to a ripple in the fabric of space. This ripple, which is defined in optics as “caustic”, provides maximum magnification and brightness. The result is proportional to the wavy surface of a pool that creates patterns of bright light at the bottom of the pool on a sunny day. The ripples on the surface act as lenses and focus the sunlight on the maximum brightness on the pool floor. This caustic makes the Earendel star emerge from the general glow of its galaxy. Its brightness is magnified a thousand times or more. At this point, astronomers are unable to determine if Earendel is a binary star, although most massive stars have at least one smaller companion star.
Webb Confirmation
Astronomers expect the Earendel to remain extremely large for years to come. It will be observed by NASA’s James Webb Space Telescope. Webb’s high sensitivity to infrared light is necessary to learn more about Earendel, because its light is stretched (shifted to red) at longer infrared wavelengths due to the expansion of the universe. “With Webb we expect to confirm that Earendel is indeed a star, as well as measure its brightness and temperature,” Coe said. These details will limit its type and stage in the astral life cycle. “We are also waiting to see that the Sunrise Arc galaxy lacks the heavy elements that form in the next generation of stars. This would suggest that Earendel is a rare, huge metal-poor star,” Coe said. Earendel’s composition will be of great interest to astronomers because it was formed before the universe was filled with heavy elements produced by successive generations of giant stars. If subsequent studies find that Earendel consists only of primordial hydrogen and helium, it would be the first evidence of the legendary Population III stars, which are supposed to be the first stars to be born after the Big Bang. Although the probability is small, Welch admits that it is tempting. “With Webb, we can see stars even further away from Arendel, which would be incredibly exciting,” Weltz said. “We will go as far as we can. I would love to see Webb break Earedel’s distance record.” The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland operates the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble Science operations. STScI operates for NASA from the Association of Universities for Astronomy Research in Washington, DC
title: “Hubble Spots Farthest Star Ever Seen " ShowToc: true date: “2022-11-04” author: “Ethel Peterson”
The most distant solitary star ever seen was recently spotted by the Hubble Space Telescope in a collaboration involving researchers from Ben-Gurion University in Israel. The newly discovered star, named Earendel (“morning star” in Old English) is estimated to be at least 50 times the mass of our sun and millions of times brighter, competing with the most massive stars known. Earendel is so far away that it took 12.9 billion years for light to reach Earth, showing us as when the universe was only 7 percent of its current age, at a time when astronomers refer to it as a redshift of 6.2 . (Redshift refers to the fact that as the universe expands, light from distant objects shifts to larger, redder wavelengths as it travels toward us.) “We hardly believed it at first, it was so much farther away than the previous farther, higher redshift star,” said astronomer Brian Welch of Johns Hopkins University in Baltimore, lead author of the paper describing the discovery, published in the journal Nature. The previous record holder with a star. Discovered by Hubble in 2018, it existed when the universe was about 4 billion years old, or 30 percent of its current age, shifting 1.5 to red. The new discovery was made from data collected during Hubble’s RELICS (Reionization Lensing Cluster Survey) program, led by co-author Dan Coe at the Space Telescope Science Institute (STScI), also in Baltimore. Professor Adi Zitrin of Ben-Gurion University, one of the study’s lead researchers, explained that a cosmic alignment of a huge cluster of galaxies between us and the distant star magnified the star at least a few thousand times. Massive bodies bend space-time to effectively create a lens in the sky. “The lens phenomenon opens a door for us to learn about dark matter and distant galaxies,” Zitrin said. The discovery “also opens a door to learn about the stars in the early universe, where we have little information about their physical characteristics and their contribution to early hydrogen ionization throughout the universe,” he added.
