Just like dust on Earth, cosmic dust is made up of molecules that have condensed and stuck together in a grain. The mystery of dust creation in the universe has finally been solved by an international team of astronomers from China, the United States, Chile, the United Kingdom, Spain, and more. They have identified a previously unknown source of dust in the universe: a Type 1a supernova interacting with gas from its surroundings.
Supernovae have been known to play a role in dust formation, and to date, dust formation has only been seen in core-collapse supernovae—the explosion of massive stars. Since core-collapse supernovae do not occur in elliptical galaxies, the nature of dust creation in such galaxies has remained elusive.
These galaxies are not organized into a spiral pattern like our Milky Way but are giant swarms of stars. This study shows that thermonuclear Type 1a supernovae, the explosion of white dwarf stars in binary systems with another star, may account for a significant amount of dust in these galaxies.
The researchers monitored a supernova, SN 2018evt, for over three years using space-based facilities like NASA’s Spitzer Space Telescope and NEOWISE missions, ground-based facilities like the Las Cumbres Observatory’s global network of telescopes, and other facilities in China, South America, and Australia. They found that the supernova was running into material previously cast off by one or both stars in the binary system before the white dwarf star exploded, and the supernova sent a shock wave into this pre-existing gas.
During more than a thousand days of monitoring the supernova, the researchers noticed that its light began to dim precipitously in the optical wavelengths that our eyes can see, and then started glowing brighter in infrared light. This was a telltale sign that dust was being created in the circumstellar gas after it cooled following the supernova shock wave passing through it.
2024-02-11 10:00:04
Original from phys.org
