Astronomers detect oldest known stardust in distant galaxy
Astronomers have spotted the oldest stardust created in the universe.
The astrophysicist Nicolas Laporte of University College London and his colleagues detected dust in a galaxy seen as it was made when the universe was 600 million years old. Laporte said “We are probably seeing the first stardust of the universe”.
The galaxy, called A2744_YD4, lies behind a galaxy cluster called Abell 2744. That cluster acts as a gravitational lens, magnifying and brightening the distant galaxy’s light by about a factor of two. The dust was revealed when the astronomers observed the galaxy with the Atacama Large Millimeter/Submillimeter Array (ALMA), an international association that includes Europe, North America, part of Asia and Chile, and created the biggest astronomical project located in Chile.
The dust comes from supernova explosions of a large amount of stars that were some of the earliest stars in the universe. Astronomers said that the first stars were formed approximately 400 million years after the Big Bang, which occurred 13.8 billion years ago. Laporte and the colleagues said that this stardust was formed 600 million years after the Big Bang and that it weighs 6 million times the mass of the sun.
The astronomers also detected positively charged oxygen atoms and a sign of hydrogen gas, which suggest the galaxy’s gas is ionized.
By now, astronomers had been investigating the history of galaxies by counting them and looking at their colors, notes chard Ellis, a cosmologist from University College London at the European Southern Observatory. Spotting dust in the universe means that an early galaxy have been formed in that area, meanwhile fewer heavy elements would point to younger and younger galaxies.
The detection of ionized oxygen could also hint that a black hole is located at the center of the galaxy A2744_YD4.
By: Esteban Daniel