Researchers study flames to understand exploding stars

Scientists studied small flames in the lab to gain insights into the titanic forces that drive supernovae – or exploding stars.

Starting from the behavior of small flames in the laboratory, a team of researchers has gained new insights into the titanic forces that drive Type Ia supernova explosions.

Aaron Jackson at the Naval Research Laboratory in Washington, D.C. and his colleagues presented their results (pdf) at the American Physical Society’s (APS) Division of Fluid Dynamics (DFD) meeting in Baltimore last week (Nov. 20-22, 2011).

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Type Ia supernovae are believed to form when a white dwarf star – the left-over cinder of a star like our sun – accumulates so much mass from a companion star that it is able to reignite thermonuclear fuel in its interior and detonate, briefly outshining all other stars in its host galaxy.

To understand the complex conditions driving this type of supernova, the researchers performed new 3-D calculations of the turbulence that is thought to push a slow-burning flame past its limits, causing a rapid detonation — the so-called deflagration-to-detonation transition (DDT).

How this transition might occur is hotly debated. Jackson and his colleagues say their research provides insights into what is happening at the moment when the white dwarf star makes the spectacular transition to supernova. Jackson said:

Turbulence properties inferred from these simulations provides insight into the DDT process, if it occurs.

The researchers say that understanding supernovae can help astronomers understand other facets of our universe.

For example, because supernovae have a characteristic brightness, astronomers use them to calculate cosmic distances. In other words, astronomers can see supernovae at great distances. They can observe their behavior to get a good estimate of their intrinsic brightnesses. Then they see how bright the supernovae appear to us from Earth in order to estimate their distances. Because they are used to calculate distances across the universe in this way, supernovae are sometimes referred to by astronomers as standard candles.

The researchers speculate that this better understanding of the physical underpinnings of the type Ia supernovae explosion mechanism will give astronomers more confidence in using Type Ia supernovae as standard candles, and thus might yield more precise distance estimates across the vast space of our universe.

Bottom line: Researchers studied the behavior of small flames in the laboratory in order to understand type Ia supernova explosions. They performed new 3-D calculations of the turbulence that is thought to push a slow-burning flame past its limits, causing a rapid detonation — the so-called deflagration-to-detonation transition (DDT). A similar mechanism might also occur in Type Ia supernovae.

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