Alissa Mezzacappa

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Early black hole formation in a core-collapse supernova will abruptly truncate the neutrino fluxes. The sharp cutoff can be used to make model-independent time-of-flight neutrino mass tests. Assuming a neutrino luminosity of 10 52 erg͞s per flavor at cutoff and a distance of 10 kpc, Super-Kamiokande can detect an electron neutrino mass as small as 1.8 eV,(More)
The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the(More)
Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and (18)O/(16)O in water and (13)C/(12)C,(More)
With the exception of the Big Bang, responsible for 1,2 H, 3,4 He, and 7 Li, stars act as sources for the composition of the interstellar medium. Cosmic rays are related to the latter and very probably due to acceleration of the mixed interstellar medium by shock waves from supernova remnants. Thus, the understanding of the abundance evolution in the(More)
In this paper, we present results from a simulation of stellar core collapse, bounce, and postbounce evolution with Boltzmann neutrino transport. We motivate the development of our Boltzmann solver in light of the sensitivity of the neutrino-heating core collapse supernova paradigm to details in the neutrino transport, particularly near the neutrinospheres,(More)
We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an " optimistic " 15 M ⊙ precollapse model, which is representative of the class of stars with compact iron cores. This model is evolved through core collapse and bounce in one dimension using multigroup(More)
The implications of the formation of strange quark matter in neutron stars and in core-collapse supernovae is discussed with special emphasis on the possibility of having a strong first order QCD phase transition at high baryon densities. If strange quark matter is formed in core-collapse supernovae shortly after the bounce, it causes the launch of a second(More)
Massive progenitor stars end their life in an explosion event with kinetic energies of the order 10 51 erg. Behind the explosion ejecta, the low density and high entropy region formed immediately after the explosion is subject to neutrino heating. The neutrinos emitted from the remnant at the center, a protoneutron star (PNS), continually heat the material(More)
Supernova simulations to date have assumed that during core collapse electron captures occur dominantly on free protons, while captures on heavy nuclei are Pauli blocked and are ignored. We have calculated rates for electron capture on nuclei with mass numbers A=65-112 for the temperatures and densities appropriate for core collapse. We find that these(More)