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Astronomers have identified Type Ia supernovae that interact with gas as a new source of cosmic dust, providing insights into the process of dust formation in elliptical galaxies.
Cosmic dust (like dust on Earth) consists of groups of molecules that condense and stick together to form particles. But the exact nature of dust production in the universe has long been a mystery. Now, however, an international team of astronomers from China, the United States, Chile, the United Kingdom, Spain, and elsewhere has made a major discovery, identifying a previously unknown source of dust in the universe: a Type Ia supernova combined with particles from the surrounding ambient gases.
The research will be published in natural astronomy Today (February 9), it was led by researcher Wang Lingzhi from the South American Astronomy Center of the Chinese Academy of Sciences.
Supernovae and dust formation
Supernovae are known to play an important role in the formation of dust, which has so far only occurred in core-collapse supernovae – explosions of massive stars. Since core-collapse supernovae do not occur in elliptical galaxies, the nature of dust production in such galaxies remains elusive.These galaxies are not organized into spirals like our own Milky Way But a huge constellation of stars.This study shows thermonuclear Type Ia supernova explosions white dwarf The combination of a star in a binary system with another star may be the source of the large amounts of dust in these galaxies.
Researchers monitored the supernova SN 2018evt for more than three years using space-based facilities such as NASA’s Spitzer Space Telescope and the NEOWISE mission, ground-based facilities such as the Las Cumbres Observatory Global Telescope Network, and other facilities in China and South America. . and Australia. They found that before the white dwarf exploded, the supernova encountered material previously released by one or both stars in the binary system, and the supernova sent a shock wave into this pre-existing gas.
Discovery and Inspiration
While monitoring the supernova for more than a thousand days, the researchers noticed that its light began to dim dramatically in the optical wavelengths our eyes can see, and then started to get brighter in infrared light. This is a clear sign that dust is being produced as the gas around the star cools after the supernova shock wave passes through it.
“The origin of cosmic dust has long been a mystery. This study marks the first detection of a significant and rapid dust formation process when a thermonuclear supernova interacts with circumstellar gas,” said Professor Wang, the study’s first author.
Research estimates that this supernova event must have produced a large amount of dust, with the amount exceeding 1% of the mass of the sun. As the supernova cools, the amount of dust produced should increase, perhaps tenfold. Although these dust factories are not as numerous and efficient as core-collapse supernovae, there may be enough thermonuclear supernovae to interact with their surroundings to become a significant or even major source of dust in elliptical galaxies.
“This study provides insights into the contribution of thermonuclear supernovae to cosmic dust, and it is expected that more such events may be discovered in the era of the James Webb Space Telescope (JWST),” said Professor Wang Lifan of Texas A&M University. Co-first author of the study. The infrared light seen by the Webb telescope is perfect for detecting dust.
“Dust is created simply by 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. of data were used for research. “One day, dust will condense into planetesimals and eventually planets. This is the creation that begins anew after the death of a star. It is exciting to understand another link in the cycle of life and death in the universe.”
Reference: “Newly formed dust in the circumstellar environment of SN Ia-CSM 2018evt”, February 9, 2024 natural astronomy.
DOI: 10.1038/s41550-024-02197-9
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