Formation and evolution of hypernova progenitors in massive binary systems

The massive stellar progenitor of a hypernova explosion and an associated gamma-ray burst must satisfy two primary constraints: (1) the outer layers of the stellar core must possess sufficient angular momentum to form a centrifugally supported torus about the collapsed central object (a Kerr black hole); and, (2) the envelope of the star must not be excessively massive or distended, so that the energetic, ultrarelativistic outflow generated by the central engine in the core of the star does not risk being smothered before it can escape from the star and expand outward to produce a gamma-ray burst. Physical processes which occur during the evolution of an isolated massive star will tend to diminish its initial angular momentum content, rendering it difficult for such a star to become a hypernova progenitor since its core will likely no longer spin rapidly enough to support a torus about its collapsed core. However, a substantial fraction of massive stars are members of binary systems. Tidal locking, mass transfer, or stellar merger in an evolved massive binary system could possibly lead to the transfer of orbital angular momentum to the core of one of the stars (or to the core of a merged star, if a common envelope develops), of sufficient magnitude to produce the core of a successful hypernova progenitor (constraint 1). Further interaction between the stars or their compact remnants could lead to the loss of the hydrogen and possibly helium envelopes of one of the stars (constraint 2). We have developed a new one-dimensional stellar evolution code that includes the effects of rotation on equilibrium stellar structure, and calculates the transport of angular momentum through the stellar interior due to convection, dynamical and secular shear instabilities, and gravity (buoyancy) waves.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Becker, John Alex, 1964-

Advisor dc:contributor.advisor

• Paul C. Joss.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28373

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28373