Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Measurements at CERN help to re-evaluate the element of life

14.01.2005


Results from experiments at CERN and the Jyväskylä Accelerator Laboratory in Finland, reported in Nature today, cast new light on the primary reaction that creates carbon in stars. All the carbon in the Universe, including that needed for carbon-based life forms such as ourselves, has been made in the hearts of stars through what is known as the “triple alpha reaction”. The new findings modify the rate at which the reaction occurs and have broad implications for astrophysics, from the formation of the first stars to the creation of the heaviest elements in supernovae.



"The connection between the subatomic world and the cosmos is fascinating. The example of carbon is an old problem with contributions from many heroes in the field. It is a pleasure to be able to answer some of the questions they have left for us. It is the technological development in the intervening years, for example at ISOLDE, that has made this possible," says from Hans Fynbo of the University of Aarhus, lead author of the paper.

The big bang created mainly only hydrogen (mass 1) and helium (mass 4), because there are no long lived atomic nuclei with mass 5 and 8 to make the bridge to heavier elements such as carbon (mass 12). But in the hearts of stars the formation of carbon is possible through the triple-alpha reaction, where three helium nuclei (alpha particles) fuse to make to make a nucleus of carbon-12.


Rather than recreate the scorching conditions inside stars, the team from CERN and eight other European universities and institutes watched the reaction unfold in reverse, as nuclei of carbon-12 broke into three alpha particles. To do this, they created boron-12 and nitrogen-12, which are short-lived isotopes of the elements that flank carbon in the Periodic Table. The boron-12 was produced at CERN’s ISOLDE facility, while the nitrogen-12 was created at the IGISOL facility at the Jyväskylä Accelerator Laboratory at the University of Jyväskylä. These unstable nuclei soon transformed into carbon-12, through beta decay, in which a proton changes into a neutron or vice versa; the carbon-12 then broke into three alpha particles.

The ISOL method – isotope separation on line - originally pioneered and developed mainly at CERN played an important role in these experiments. “While ISOLDE at CERN could make the boron-12, IGISOL in Jyväskylä was needed to produce the nitrogen-12. This facility in Finland was specifically developed to complement ISOLDE’s performance through its ability to produce very short-lived radioisotopes of chemically reactive elements such as nitrogen," said Juha Äysto, head of the group responsible for the experiment at the University of Jyväskylä.

By measuring precisely the timing and energies of alpha particles shooting from the samples, the researchers were able to infer the energy states of the carbon nuclei just before decay. With this information in hand, they were able to determine the rate for the triple alpha process over a wide range of temperatures, from 0.01 – 10 billion K.

For the conditions in most stars, the researchers’ calculated rates for the triple alpha process agree with previous calculations. But their findings suggest the triple alpha rate at the relatively low temperatures of the Universe’s first stars (around 0.05 billion K), which began without carbon, was much faster. This in turn implies that the amount of carbon that could catalyze hydrogen burning in the first stars was produced twice as fast as previously thought.

At high temperatures, above 1 billion K, the new results indicate that the triple alpha process would work significantly slower than previous estimates, modifying the process of element production - nucleosynthesis – in supernovae. These explosions of old massive stars are a major source of the heaviest elements, those more massive than iron, through interactions in the surrounding shock wave. The new results suggest a reduction in the amount of nickel-56 produced with subsequent effects for heavier elements.

This work was carried by a team from CERN and eight other European universities and institutes.

James Gillies | alfa
Further information:
http://www.cern.ch

More articles from Physics and Astronomy:

nachricht SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>