Synopsis: Cosmic backtracking

More accurate predictions of the silicon content in meteoritic grains allow for a better understanding of the exploding stars that produced them.
Synopsis figure
Credit: NASA/JPL-Caltech

Exploding stars called novae are thermonuclear outbursts triggered when a white dwarf star gravitationally captures hydrogen-rich material from a nearby companion star. A number of meteoritic grains from the early solar system have been discovered that may have been produced in novae. If so, the ratios between different isotopes of silicon in these grains may reflect conditions during the nova outburst.  In order to predict the isotopic ratios expected in these grains and compare with the observed values, it is critical to understand the nuclear reactions that lead to silicon nucleosynthesis.

Writing in Physical Review C, Kiana Setoodehnia and colleagues at McMaster University in Canada, and collaborators in Germany and the US, have examined the 29P(p,γ)30S reaction, which affects the synthesis of silicon in novae. (Both 29P and 30S are unstable and decay to silicon isotopes.)

By accurately measuring the energies of excited states in 30S, Setoodehnia et al. have been able to calculate the rate of the 29P(p,γ)30S reaction with improved precision and find that it is significantly higher (by about a factor of 10 for certain temperatures) than previously thought. A new excited state—seen here for the first time—makes a significant contribution to the reaction rate near the temperatures that occur during a nova outburst.

The impact of Setoodehnia et al.’s results on predicting silicon isotopic ratios in models of novae will likely be significant, and will be explored in future work. – Brad Filippone


More Features »


More Announcements »

Subject Areas

AstrophysicsNuclear Physics

Previous Synopsis

Next Synopsis

Particles and Fields

Leveraging the LHC advantage in energy

Read More »

Related Articles

Viewpoint: Spinning Black Holes May Grow Hair

Viewpoint: Spinning Black Holes May Grow Hair

A spinning black hole may lose up to 9% of its mass by spontaneously growing “hair” in the form of excitations of a hypothetical particle field with a tiny mass. Read More »

Synopsis: Proton Loses Weight
Particles and Fields

Synopsis: Proton Loses Weight

The most precise measurement to date of the proton mass finds a value that is 3 standard deviations lower than previous estimates. Read More »

Synopsis: A Reionization Filter for the Cosmic Microwave Background

Synopsis: A Reionization Filter for the Cosmic Microwave Background

A new method of analyzing cosmic microwave background data could isolate signatures from the so-called reionization period that occurred a few hundred million years after the big bang. Read More »

More Articles