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"Everything should be as simple as it is, but not simpler", Albert Einstein
Browsing All Posts filed under »NUCLEAR ASTROPHYSICS«
Carbon’s Hoyle state calculated at long last
By calculating the behaviour of protons and neutrons inside carbon nuclei from first principles, physicists in Germany and the US have identified the shape of carbon’s Hoyle state – which is an important step in the production of heavy elements inside stars. The researchers found the state to have an unusual bent structure, a finding […]
The Origin of the Elements
November 22, 2012
The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present […]
Tritium as an Anthropic Probe
July 11, 2012
Andrew Gould (Ohio State) I show that if tritium were just 20 keV lighter relative to helium-3, then the current deuterium burning phase of pre-main-sequence stellar evolution would be replaced by deuterium+tritium burning. This phase would take place at the same temperature but would last a minimum of 4 times longer and a maximum of […]
Axion Dark Matter and Cosmological Parameters
February 23, 2012
Blame dark matter underdog for mystery missing lithium by David Shiga AN UNDERDOG dark-matter particle could explain why the universe seems strangely low on lithium. If the idea holds up, it will be a boon in the hunt for dark matter, the stuff needed to account for 80 per cent of the universe’s matter. In the […]
Solar Neutrinos in 2011
January 31, 2012
Alvaro Chavarria I give an overview of the recent developments in the solar neutrino field. I focus on the Borexino detector, which has uncovered the solar neutrino spectrum below 5 MeV, providing new tests and confirmation for solar neutrino oscillations. I report on the updated measurements of the 8B solar neutrino flux by water Cherenkov […]
Earthly machine recreates star’s sizzling-hot surface
January 13, 2012
Since we can’t go to the stars yet, let’s bring the stars to us. In a giant X-ray-producing facility, astronomers and plasma physicists have heated a cigar-sized sample of gas to over 17,000 degrees Fahrenheit in order to replicate the surface of stars called white dwarfs. “As an astronomer, I am used to looking at […]
The effect of 12C + 12C rate uncertainties on the evolution and nucleosynthesis of massive stars
January 6, 2012
M. E. Bennett, R. Hirschi, M. Pignatari, S. Diehl, C. Fryer, F. Herwig, A. Hungerford, K. Nomoto, G. Rockefeller, F. X. Timmes, M. Wiescher The 12C + 12C fusion reaction has been the subject of considerable experimental efforts to constrain uncertainties at temperatures relevant for stellar nucleosynthesis. In order to investigate the effect of an […]
The Supernova Triggered Formation and Enrichment of Our Solar System
November 3, 2011
M. Gritschneder, D. N. C. Lin, S. D. Murray, Q.-Z. Yin, M.-N. Gong We investigate the enrichment of the pre-solar cloud core with short lived radionuclides (SLRs), especially 26Al. The homogeneity and the surprisingly small spread in the ratio 26Al/27Al observed in the overwhelming majority of calcium-aluminium-rich inclusions (CAIs) in a vast variety of primitive […]
Measuring elusive neutrinos flowing through the Earth, physicists learn more about the sun
October 7, 2011
Using one of the most sensitive neutrino detectors on the planet, an international team including physicists Laura Cadonati and Andrea Pocar at the University of Massachusetts Amherst are now measuring the flow of solar neutrinos reaching earth more precisely than ever before. The detector probes matter at the most fundamental level and provides a powerful […]
Stellar Nucleosynthesis Nuclear Data Mining
October 6, 2011
Boris Pritychenko Stellar nucleosynthesis is an important nuclear physics phenomenon that is responsible for presently observed chemical elements and isotope abundances. It is also one of the corner stone hypotheses that provides basis for our understanding of Nature. Its theoretical predictions are often verified through the astrophysical observation and comparison of calculated isotopic abundances with […]
Nucleosynthesis of r-Process Elements by Jittering Jets in Core-Collapse Supernovae
October 4, 2011
Oded Papish, Noam Soker We calculate the nucleosynthesis inside the hot bubble formed in the jittering-jets model for core collapse supernovae (CCSNe) explosions…. Read more: http://arxiv.org
Cosmic crashes forging gold: Nuclear reactions in space do produce the heaviest elements
September 9, 2011
Collisions of neutron stars produce the heaviest elements such as gold or lead. The cosmic site where the heaviest chemical elements such as lead or gold are formed has most likely been identified: Ejected matter from neutron stars merging in a violent collision provides ideal conditions. In detailed numerical simulations, scientists of the Max Planck […]
The Star That Should Not Exist
August 31, 2011
A team of European astronomers has used ESO’s Very Large Telescope (VLT) to track down a star in the Milky Way that many thought was impossible. They discovered that this star is composed almost entirely of hydrogen and helium, with only remarkably small amounts of other chemical elements in it. This intriguing composition places it […]
Star power: Small fusion start-ups aim for break-even
August 16, 2011
Nuclear fusion will cost a fortune – or will it? A new wave of upstart companies think they’ve found cheaper, quicker ways to build a second sun A VAST earth platform looms into view above the treetops of Cadarache in France’s sultry south-east. It measures 1 kilometre long by 400 metres wide, and excavators dotted […]
Cosmic-ray physics with IceCube
July 11, 2011
IceCube as a three-dimensional air-shower array covers an energy range of the cosmic-ray spectrum from below 1 PeV to approximately 1 EeV. This talk is a brief review of the function and goals of IceTop, the surface component of the IceCube neutrino telescope. An overview of different and complementary ways that IceCube is sensitive to […]
Standard Big-Bang Nucleosynthesis up to CNO with an improved extended nuclear network
July 9, 2011
Primordial or Big Bang nucleosynthesis (BBN) is one of the three strong evidences for the Big- Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation. In this study, we improve the standard BBN calculations taking into account new nuclear physics analyses and we enlarge the nuclear network until Sodium. […]
Supernovae, Neutrinos, and the Chirality of the Amino Acids
June 25, 2011
Abstract: A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is described. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of […]
NASA Mission Suggests Sun And Planets Constructed Differently
June 23, 2011
WASHINGTON — Analysis of samples returned by NASA’s Genesis mission indicates our sun and its inner planets may have formed differently than scientists previously thought. The data revealed slight differences in the types of oxygen and nitrogen present on the sun and planets. The elements are among the most abundant in our solar system. Although […]
A step closer to solving one of the biggest mysteries in fundamental physics?
June 15, 2011
Where did all the matter in the universe come from? This is one of the biggest mysteries in fundamental physics and exciting results released on 15 June 2011 from the international T2K neutrino experiment in Japan could be an important step towards resolving this puzzle. The intriguing results indicate a new property of the enigmatic particles known […]
Chemistry and the Universe
June 9, 2011
Chemistry, the study of the intricate dances and bondings of low-energy electrons to form the molecules that make up the world we live in, may seem far removed from the thermonuclear heat in the interiors of stars and the awesome power of supernovas. Yet, there is a fundamental connection between them. To illustrate this connection, […]
Carina Nebula: Pumping More Than Just Iron
May 25, 2011
We are all just star stuff… But when it comes to the elements produced by a star, it just doesn’t get any heavier than iron. So how do more exotic elements come into existence? Try the Great Cosmic Recycler – supernova. Its energy disperses newly synthesized materials right into the interstellar neighborhood where an enriched […]
The carbon challenge
May 9, 2011
1. Helium burning “…In the first-generation stars the ash resulting from hydrogen burning via the p-p chain is entirely helium-4, the creation of heavier elements having been blocked by the instabilities at A=5 and A=8. These are referred to as the mass gaps. Since carbon-12, the fourth most abundant nuclear species observed in the universe, […]
January 3, 2013
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