white dwarfs tagged posts

As dying stars take their final few breaths of life, they gently sprinkle their ashes into the cosmos through the magnificent planetary nebulae. These ashes, spread via stellar winds, are enriched with many different chemical elements, including carbon.

Findings from a study published today in Nature Astronomy show that the final breaths of these dying stars, called white dwarfs, shed light on carbon’s origin in the Milky Way.

“The findings pose new, stringent constraints on how and when carbon was produce...

Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526 © NASA/ESA

A new math model details a way that dead stars called white dwarfs could detonate, producing a type of explosion that is instrumental to measuring the extreme distances in our universe. The mechanism, described in the Monthly Notices of the Royal Astronomical Society, could improve our understanding of how Type Ia supernovae form. “Type Ia supernovae are extremely important objects in physics, best known for their role in revealing that the expansion of the universe is accelerating,” said Prof. Saavik Ford. “The problem is that people do not agree on exactly how Type Ia supernovae come to be.”

Current research indicates that Type Ia supernova explosions originate from binary star systems – two stars orbiting one...

Supernova G1.9+0.3. Credit: NASA/CXC/CfA/S. Chakraborti et al.

Scientists have used data from NASA’s Chandra X-ray Observatory and the NSF’s Jansky Very Large Array to determine the likely trigger for the most recent supernova in the Milky Way. They applied a new technique that could have implications for understanding other Type Ia supernovas, a class of stellar explosions that scientists use to determine the expansion rate of the Universe.

Astronomers had previously identified G1.9+0.3 as the remnant of the most recent supernova in our Galaxy, Type Ia category. It is estimated to have occurred about 110 years ago in a dusty region of the Galaxy that blocked visible light from reaching Earth...

Diagnostics of the pulsations before (red), during (green) and after (blue) the seventh outburst observed on PG 1149+057. The top panel shows the K2 light curve, while the bottom panels show the FT of each subset. Signals exceeding the significance thresholds (see text) are marked with appropriate-colored dots and show differences in the excited pulsation spectra. Amplitudes are essentially all lower after outburst, but subsequently grow (see Figure 5). Significant pulsations are also visible during the brightening event (green squares), and appear at shorter periods (higher frequencies) and higher amplitudes. The top right panel shows the window function of each subset. Credit: http://arxiv.org/pdf/1507.06319.pdf

Research confirms rapid brightening events in otherwise normal pulsating whi...