Here comes another variation to the Standard Candle .. this time for the cornerstone .. Type IA Supernovae !!! …
The best way to measure dark energy just got better
Quote:
Type Ia supernovae are used as standard candles, meaning they have a known intrinsic brightness. However, they're not all equally bright. Astronomers have to correct for certain variations. In particular, there is a known correlation between how quickly the supernova brightens and dims (its light curve) and the intrinsic peak brightness.
Even when astronomers correct for this effect, their measurements still show some scatter, which leads to inaccuracies when calculating distances
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Foley discovered that after correcting for how quickly Type Ia supernovae faded, they show a distinct relationship between the speed of their ejected material and their color: the faster ones are slightly redder and the slower ones are bluer.
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Previously, astronomers assumed that redder explosions only appeared that way because of intervening dust, which would also dim the explosion and make it appear farther than it was. Trying to correct for this, they would incorrectly calculate that the explosion was closer than it appeared. Foley's work shows that some of the color difference is intrinsic to the supernova itself.
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His study includes 100 Supernovae. The assumption that all Supernovae are on average, the same colour, and redder due to intervening dust, now seems to be outdated.
Cheers