Researchers discover cosmic dust storms from Type 1a supernova

Cosmic dust, like dust on Earth, is made up of groups of molecules that have condensed and stuck together into a grain. But the exact nature of dust creation in the universe has long been a mystery. But today, an international team of astronomers from China, the United States, Chile, the United Kingdom, Spain, etc., made an important discovery by identifying a previously unknown source of dust in the universe: a type 1a supernova interacting with gas from its environment.

The study was published in Natural astronomy on February 9, and was led by Professor Wang Lingzhi of the South American Astronomy Center of the Chinese Academy of Sciences.

Supernovae are known to play a role in dust formation, and to date, dust formation has only been observed in core collapse supernovae, i.e. exploding stars massive. Since core-collapse supernovae do not occur in elliptical galaxies, the nature of dust creation in these galaxies has remained elusive.

These galaxies are not organized in a spiral like our Milky Way but are giant swarms of stars. This study shows that type 1a thermonuclear supernovae, the explosion of white dwarf stars in binary systems with another star, could be the source of a significant amount of dust in these galaxies.

Researchers monitored a supernova, SN 2018evt, for more than three years using space facilities such as NASA’s Spitzer Space Telescope and NEOWISE missions, ground-based facilities such as NASA’s Global Telescope Network. Las Cumbres Observatory and other facilities in China, South America, and Australia. They found that the supernova ran into material previously shed by one or both stars in the binary system before the white dwarf star exploded, and the supernova sent a shockwave through this pre-existing gas.

During more than a thousand days of monitoring the supernova, researchers noticed that its light began to fade precipitously in the optical wavelengths our eyes can see, then began to shine 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 that passed through it.

“The origins of cosmic dust have long been a mystery. This study marks the first detection of a significant and rapid dust formation process in thermonuclear supernova interacting with circumstellar gas,” said Professor Wang, first author of the study.

The study estimates that a large amount of dust must have been created by this supernova event, an amount equal to more than 1% of the mass of the sun. As the supernova cools, the amount of dust created is expected to increase tenfold. Although these dust factories are not as numerous or as efficient as core-collapse supernovae, there may be enough thermonuclear supernovae interacting with their surroundings to constitute a significant, or even dominant, source of dust in elliptical galaxies.

“This study provides insight into the contribution of thermonuclear supernovae to cosmic dust, and we can expect more such events to occur in the era of the James Webb Space Telescope (JWST),” he said. said Professor Wang Lifan of Texas A&M University, a co-first author of the study. The Webb telescope sees infrared light, perfect for detecting dust.

“Dust creation is simply gas getting cold enough to condense,” said Professor Andy Howell of Las Cumbres Observatory and the University of California, Santa Barbara. Howell is the principal investigator of the Global Supernova project whose data was used in the study. “One day this dust will condense into planetesimals and, ultimately, planets. It is a creation that begins anew in the wake of stellar death. It is exciting to understand another link in the circle of life and death In the universe.”