• Stellar Evolution, accented with Modules for Experiments for Stellar Astrophysics (MESA) • Supernovae, with emphasis on their progenitor evolution, explosion, and nucleosynthesis • Cosmic chemical evolution, the evolution of every isotope at every point in spacetime • Astrobiology, the synthesis and delivery of bioessential elements to habitable systems • Gamma-ray astronomy, particularly fro...

We predict that Coulomb explosion of a nanoscale cluster, which is ionized by high-intensity laser radiation and has a naturally occurring spatial density profile, will invariably produce shock waves. In most typical situations, two shocks, a leading and a trailing one, form a shock shell that eventually encompasses the entire cluster. Being the first example of shock waves on the nanometer sca...

• Stellar Evolution, accented by Modules for Experiments for Stellar Astrophysics (MESA) • Supernovae, with emphasis on their progenitor evolution, explosion, and nucleosynthesis • Cosmic chemical evolution, the evolution of every isotope at every point in spacetime • Astrobiology, the synthesis and delivery of bioessential elements to habitable systems • Gamma-ray astronomy, particularly from ...

The astrophysical p-process is responsible for the origin of the proton rich nuclei,which are heavier than iron. A huge network involving thousands of reaction rates is necessary to calculate the final p-abundances. But not all rates included in the network have a strong influence on the p-nuclei abundances. The p-process was investigated using a full nuclear reaction network for a type II supe...

We have studied the sensitivity to variations in the the triple alpha and C(α, γ)O reaction rates of the production of Al, Ti, and Fe in core-collapse supernovae. We used the KEPLER code to model the evolution of 15M⊙, 20M⊙, and 25M⊙ stars to the onset of core collapse and simulated the ensuing supernova explosion using a piston model for the explosion. Calculations were performed for the Ander...

The concepts surrounding a Comprehensive Test Ban Treaty can be traced back to the early 50’s and are well described in Sullivan (1998). The verification regime of the Comprehensive Nuclear-Test-Ban Treaty requires the establishment of an International Monitoring System (IMS) based on four different monitoring technologies: seismic, hydroacoustic, infrasound and radionuclide. The first three te...

Aspherical explosion models for the hypernova (hyper-energetic supernova) SN 1998bw are presented. Nucleosynthesis in aspherical explosions is examined with a two-dimensional hydrodynamical code and a detailed nuclear reaction network. Aspherical explosions lead to a strong α-rich freezeout, thus enhancing the abundance ratios [Ca, Ti, and Zn / Fe] in the ejecta. The nebular line profiles of th...

We address the stability of multicharged finite systems driven by Coulomb forces beyond the Rayleigh instability limit. Our exploration of the nuclear dynamics of heavily charged Morse clusters enabled us to vary the range of the pair potential and of the fissibility parameter, which results in distinct fragmentation patterns and in the angular distributions of the fragments. The Rayleigh insta...

We analyze the possible existence of a pulsational instability excited by the ǫ-mechanism during the last few centuries of evolution of a Chandrasekhar mass white dwarf prior to its explosion as a Type Ia supernova. Our analysis is motivated by the temperature sensitivity of the nuclear energy generation rate (∼ T 23) in a white dwarf whose structural adiabatic index is near 4/3. Based upon a l...

After the September 11, 2001 terrorist attacks on the World Trade Center and the Pentagon, many scholars, journalists, and public officials expressed fear about the security of nuclear facilities in the United States. Terrorists could attack military bases, weapons in transit, or nuclear weapons production and dismantlement plants in order to steal a weapon or its components. Terrorists might a...