For only the second time, astronomers detected a strange flash of light during a supernova


A stunning flash of ultraviolet light from an exploding white dwarf has been detected only a second time by astronomers, and may give researchers important clues about the demise of these ancient, spent stars.

Researchers found out about this unusual supernova – called SN2019yvq – last December, the day after the explosion. Within the hour, scientists classified the incident as a kind of aya supernova – not an unusual stellar event, usually at least, except this time it was accompanied by an extremely rare flash of ultraviolet light.

“These are the most common explosions in the universe,” says astrophysicist Adam Miller of Northwestern University.

“But what’s special is this UV flash. Astronomers have searched for it for years and never found it. To our knowledge, this is actually only the second time a UV flash has been seen with a type of IA supernova.”

Composite image of SN2019yvq (blue dot). (ZTF / Northwestern / Caltech)

SN2019yvq occurred in a galaxy about 140 million light years from Earth, with a rare UV flash seen before emission for a few days.

As for what was behind the strange light, the team says they are not sure yet, because the white dwarf – the exhausted stellar remnants that are usually comparatively cool – usually has the heat required for such UV light. Not hot enough to generate. .

“Most supernovas are not hot, so you don’t get very intense UV radiation,” Miller says.

“Something unusual happened to this supernova to create a very hot event.”

While the exact mechanism responsible for the ongoing comments or flash of SN2019yvq is expected to narrow within the next year, there currently remain four possible culprits that could have triggered these incidents.

Potentially, the researchers believe, the white dwarf could become unstable after consuming stellar material from a companion star in a binary system, sparking UV flash with a collision of material between the two.

Alternatively, mixing between the inner core and outer layers of the white dwarf in a flash may result in a dramatic increase in heat, or the ignition of carbon from helium into the star.

Finally, it is possible that the two white dwarfs merge, with the SN2019yvq’s UV flash representing an explosion, as an emitting material from both wires came into contact.

While we can’t be sure which explanation is yet the best match for what transpired in SN 20179yvq, as this incredible stellar event begins to freeze, the picture is expected to be clear.

“As time passes, the blast material moves away from the source,” Miller says. “As with that material, we can see deeper and deeper. After a year, the material will be so thin that we will see all the way to the center of the explosion.”

At that point, the researchers say that we should finally be able to understand what brilliantly this white dwarf exploded, and the answers can teach us about how iron produced in supernovae is distributed in space Is (eventually helping to create the seed planet).

It may be able to help us get to know some unknown people around dark energy, which is thought to influence how fast the universe is expanding.

“If there is a type of IA supernova in a distant galaxy, we can use it to measure a combination of distance and velocity that allows us to determine the acceleration of the universe,” Miller says.

“Dark energy remains a mystery. But this supernova is the best way to investigate and understand dark energy.”

The findings are stated in The Astrophysical Journal.

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