NuSTAR Finds New Clues to ’Chameleon‘

This image from NASA’s Chandra X-ray Observatory shows spiral galaxy NGC 7331, center, in a three-color X-ray image. Red, green and blue colors are used for low, medium and high-energy X-rays, respectively. An unusual supernova called SN 2014C has been spotted in this galaxy, indicated by the box.
Credits: NASA/CXC/CIERA/R.Margutti et al

In the new study, NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) satellite, with its unique ability to observe radiation in the hard X-ray energy range—the highest-energy X-rays—allowed scientists to watch how the temperature of electrons accelerated by the supernova shock changed over time. They used this measurement to estimate how fast the supernova expanded and how much material is in the external shell.

To create this shell, SN 2014C did something truly mysterious: it threw off a lot of material—mostly hydrogen, but also heavier elements—decades to centuries before exploding. In fact, the star ejected the equivalent of the mass of the sun. Normally, stars do not throw off material so late in their life.

“Expelling this material late in life is likely a way that stars give elements, which they produce during their lifetimes, back to their environment,” said Margutti, a member of Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics.

The complete article thanks to Elizabeth Landau, Jet Propulsion Lab is here.