May 6, 2022 –
“Understanding the origins of Type Ia supernovae is one of the most debated issues in astrophysics,” explains Dr. Samar Safi-Harb, Canada’s Level 1 Research Department in Extreme Astrophysics at the University of the University of Natural Sciences and Engineering. (NSERC). Manitoba.
Dr. Samar Safi-Harb
Safi-Harb is working with visiting scientist Dr. Gilles Ferran of Rikagaku Kenkyūjo, Institute of Physical and Chemical Research in Japan (RIKEN), to study the remains of stellar explosions.
Type Ia supernovae are used by astrophysicists as “standard candles”, the term “meter” used by astrophysicists to estimate distances to galaxies in the universe and to show that the expansion of the universe is accelerating. These cosmic explosions are considered standards for measuring distant celestial objects because of the way they are thought to form and shine.
“Generally speaking, there are two different types of supernovae,” explains Safi-Harb: explosions resulting from the deaths of massive stars creating neutron stars and black holes, and type Ia supernovae traditionally thought to be the result of the death of a white dwarf star (a consequence of the sun as stars after they die) in binary systems. “However, how exactly these stars explode is still unclear.”
Recent studies show that the second mechanism has a very interesting option. If two white dwarf stars orbit each other, a back-to-back detonation could cause one of them to explode like a supernova, while the other star survives and escapes at super-fast speeds, like a billiard ball. In fact, several high-speed white dwarfs discovered in 2018 are thought to have survived such a Type Ia explosion.
In some cases, a supernova can launch a star into space like a billiard ball
This model of explosion is called “Dynamically driven, double-degenerative, double-detonation” model or D6 for short. Such explosions will form white dwarfs at high speed and can affect the way we look at the effects of Ia explosions that drive the evolution of the galaxy.
Ferran notes: “This prompts us to review previous studies of supernova remnants and emphasizes the need to use advanced 3D modeling techniques to better understand the mechanisms involved.
Dr. Gilles Ferran
Ferran and an international team of researchers from Japan, Canada and France have a paper in the scientific journal Astrophysical Journal detailing how their modeling of the remnant Ia from a supernova resulting from the D6 explosion reveals asymmetry even after thousands of years of evolution. They show that the remains of these explosions reveal prints that can be traced by X-ray observations, contrary to what is usually thought.
This article is the first effort to use 3D state-of-the-art simulations of the D6 Type Ia supernova conducted on a supercomputer to model and map the effects of a supernova explosion, following its evolution until it becomes a mature supernova remnant.
The simulations show that there are some interesting, long-lasting signatures inside the remnant of the supernova, including a “shadow” or dark spot surrounded by a bright ring, and that the remnants of type Ia explosions are not necessarily symmetrical, as is commonly believed.
“This is very important, because this study introduces us to a new way of studying the mechanism of a type Ia supernova through its remainder,” Ferran said.
“Given the emerging diversity of Ia supernovae and their imprints on their remains, this may require rewriting some textbooks and will lead to future observations,” added Safi-Harb.
Research at the University of Manitoba is partially supported by Government funding from the Canadian Research Support Fund.
Chris Rutkowski
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