What can we learn about the large-scale properties of our universe from Type Ia supernovae — cosmic flashes thought to be caused by the explosions of white dwarfs? The answer may depend on the shared traits of pairs of supernova siblings.
This artist’s rendering depicts the typical Type Ia supernova mechanism, in which a white dwarf siphons mass from its companion, exceeds the Chandrasekhar mass, and explodes. [NASA/CXC/M. Weiss]How do we measure vast distances — and, correspondingly, the cosmological properties of our universe? One of astronomers’ go-to methods relies on Type Ia supernovae, explosions thought to have a fixed intrinsic luminosity.
By comparing the measured brightness of these explosions to their expected intrinsic luminosity, we can obtain a quantity known as the distance modulus, which tells us how far away the supernova occurred.
But there’s a catch: though Type Ia supernovae all have roughly the same intrinsic luminosity, they still exhibit some variation — scatter — in their natural peak brightness. This intrinsic scatter reduces how accurately we can measure their distance.
Taking the Blame for Scatter
Astronomers are still working to understand what causes the intrinsic scatter in supernova distance modulus. Is it differences in the atmospheres ...