UCRL-ID-123671

Hydrodynamics and Nucleosynthesis in Neutron Stars, Supernovae, and the Early Universe

Grant Mathews

March 19%

This is an informal report intended primarily for internal or limited external distribution. The opinions and conclusions stated are those of the author and may or may not be those of the Laboratory. Work performed under the auspices of the US. Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.

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3.05 ' I

FY45 Annual Report Form Anhual Report Contributioi Project Tit le: Tracking Code: 94-ERD-030 Hydrodynamics and Nucleosynthesis in Neutron Stars, Supernovae, and the Early Universe

Principal Investigator: Grant Mathews Employee number: 574625 Core Competency: Nuclear/Atornic Science & Tech

Annual Report Authors: Mathews, Grant J.

Annual Report Description: Character Count: 4129 In this proposal we,apply laboratory expertise in integrated numerical modeling of

relativistic hydrodynamics, radiation transport, and thermonuclear reaction rates to forefront areas of basic research in areas of astrophysical interest. These studies include the last s tages of a merging neutron-star binary system; the pre-collapse, collapse, and post- collapse evolution of supernova cores; the violent relaxation, protogalactic mergers, and stellar nucleosynthesis associated with galaxy formation and studies of primordial nucleosynthesis during the big bang. This project provides unique high-visibility solutions to current technical problems while enriching current laboratory capabilities in the relevant disciplines.

In FY95 the first systematic computations of instabilities in the final orbits of two neutron stars were completed. A new general relativistic instability was discovered and published in Physical Review Letters (Wilson and Mathews 1995). It was observed that nonlinear effects of the strong graviational fields of the neutron stars cause the stars to separately collapse into individual black holes seconds before the stars actually merge. This surprising result significantly impacts the development of next generation gravity wave detectors and theoretical studies of astrophysical gamma-ray bursts.

We have made a preliminary study of the collapse heating as a source for gamma- ray bursts. We also showed that the mass loss from the stars is too little to contribute to heavy element nucleosynthesis in the Galaxy. This work was the subject of Jim Wilson's 1995 Marcel Grossman Award.

The work on supernova cores has considered effects of weak interaction rates on precollapse structure, phase transitions in nuclear matter during the collapse, and the evolution of material in the neutrino heated baryon wind from the proto-neutron star. W e completed and submitted .a study of nickel nuclei and calculated electron capture rates for several nuclei which wereadded to our data base of key electron capture and beta rates for stellar collapse. This work has stimulated several experimental projects to test our calculations. We also completed and published a paper (Gentile e t al 1995) on the effects of a Q-star equation of state on supernovae. Studies of convection in supernovae have been run but not yet to sufficiently late time.

We studied the evolution of the light elements Li, Be, and B in the halo and disk phase (Yoshii et al 1995) and showed that accretion on to halo stars passing through the galactic disk can mimic a big bang origin. We also studied globular cluster formation in the protogalaxy and the globular cluster metallicity distribution (Lee e t al 1995). In separate works, hydrodynamic simulations of three-dimensional cloud mergers were undertaken to . 0 . , . I I . . .. . . . . .I . . . . * . .

simulate globular cluster tormation. An exact scheme tor solving tne ciouu-in-ciouu problem in Press Schechter theory (Jedamzik 1995) was also developed. W e developed chemical evolution models to study abundance gradients in disk galaxies as a means to constrain the initial mass function for star formation. In a work near completion, we developed a model to explain both the observed microlensing events from the MACHO collaboration, and the observation of hot X-ray gas in galactic clusters. In this model, the microlensing objects a r e stellar remnants whose ejecta exited the galaxies to become the hot gas of the clusters.

Studies of constraints on primordial isocurvature baryon (PIB) fluctuations were completed and submitted. These studies found new significant constraints which limit this possible cosmological model. New derivations of the upper and lower limits to the universal baryon density were also completed and published (Mathews et a1 1995; Jedamzik e t al 1995). A new estimate of the primordial helium abundance was derived. A significant review paper of this field was written and submitted (Mathews and Schramm 1995). The new upper limits on the baryon content of the universe may solve some of the questions raised by the MACHO and hot X-ray gas observations.

3.05 ,

. FY95 Annual Report Form Student/Post Doc Project Title: Tracking Code: 94-ERD-030 Hydrodynamics and Nucleosynthesis in Neutron Stars, Supernovae, and the Early Universe

StudenVPost Doc Info ... Year First Name Last Name University Name (if applicable)

1994 1995

Karsten Pedro

Jedamzik Marronetti Notre Dame

Postdoc Status

.- FY95 Annual Report Form 3.05 Publications ,

Project Title: r.

Tracking Code: 94-ERD-030 .. I Hydrodynamics and Nucleosynthesis in Neutron Stars, Supernovae, and the Early Universe .

Pub Ne Title Journal

UCRL-JC Inhomogeneous Primordial Astrophysical - 1 1 7 4 5 Nucleosynthesis and New Hournal 8 Abundance Constraints on

$/Omega-b$

. UCRL-JC Absence of a Lower Limit Astrophysical - 1 1 7 4 8 on $/Omega-b$ in Journal 7 Inhomogeneous Primordial

Nucleosynthesis

UCRL-JC A Merger Model and - 1 1 8 3 1 Globular Cluster Journal 9 Formation

UCRL-JC Beryllium and Boron Astrophysical - 1 1 8 3 8 Nucleosynthesis and New Journal 8 Interstellar Accretion

Astrophysical

Vol Page 'Authors Pub Type

Mathews, G. J.; Refereed Kajino, T.; Orito, M. publication

4 4 1 4 6 5 Kedamzik, K.; Refereed Mathews, G. J.; publication Fuller, G. M.

449 6 1 6 Lee, S.; Schramm, D. Refereed N.; Mathews, G. J. publication

4 4 7 1 8 4 Yoshii, Y.; Mathews, Refereed G. J.; Kajino, T. publication

Instabilities in Close Phys. Rev. Lett. 7 5 41 6 1 Wilson, J. R. and Refereed Neutron Star Binaries Mathews, G. J. publication

UCRL-JC Relativistic Neutron Star - 1 1 8 3 3 Binary Coalescence Singapore 0

World Scientific:

Q-Star Equation of State and the Prompt Shock in Supernovae

Physical Review D

Wilson, J. R. and Refereed Mathews, G. J. publication

Gentile, N. A.; Refereed Hughes, J.; and publication Mathews G. J.

3.05 FY95 Annual Report Form A wards Project Title: Tracking Code: 94-ERD-030 Hydrodynamics and Nucleosynthesis in Neutron Stars, Supernovae, and the Early Universe

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Year First Name Last Name Sponsor 1994 James Wilson Award Marcel Grossman Award

Int. Center for Ret. Astrophys., Int. Center for Theor. Phys., Int. Sci. Foul

Year First Name Last Name Sponsor 1994 Grant Mathews American Physical Society Award Fellow in Physics