Dust formation and nucleosynthesis in the nova outburst

Journal Article · Tue Mar 25 04:00:00 EST 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.53312· OSTI ID:21165654

Starrfield, S; Gehrz, R D; Truran, J W ^[1]

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1. Department of Physics and Astronomy, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287-1504 (United States)

The nova outburst is a consequence of the accretion of hydrogen-rich material onto a white dwarf (WD) in a close binary system. The strong degeneracy of the massive WD prevents the expansion of the gas and drives the temperatures in the nuclear burning region to values exceeding 10{sup 8}K under all circumstances. As a result, a major fraction of the CNO nuclei in the envelope are transformed into {beta}-decay nuclei. The energy released from the decay of these nuclei is responsible for ejecting 10{sup -5}M{sub {center_dot}} to 10{sup -4}M{sub {center_dot}} of gas at high velocities. A major fraction of novae in outburst are observed to form dust in the ejected matter and we review the infrared (IR) observations which reveal the onset and evolution of this dust formation phase. We discuss the characteristics of nova dust and show that it may be the most interesting dust produced by any astrophysical object. IR observations show, in addition, that novae appear capable of condensing dust with at least four different chemical and mineral compositions. We argue that the class of ONeMg novae may form dust grains that carry the Ne-E and {sup 26}Mg anomalies observed in meteoritic grains. We also report on the results of new calculations of thermonuclear runaways on both carbon-oxygen and oxygen-neon-magnesium white dwarfs using our one-dimensional, fully implicit, hydrodynamic stellar evolution code that includes a large nuclear reaction network. We have updated both the nuclear reaction network and the nuclear reaction rates. Our results show that the changes in the reaction rates and opacities produce quantitative changes with respect to our earlier studies. The causes are (1) that the new opacities are larger than those we previously used, which results in less mass being accreted onto the white dwarf, and (2) that the protoncapture reaction rates for some of the intermediate mass nuclei near {sup 26}Al have increased so that the evolution to higher mass nuclei is enhanced.

• OSTI ID: 21165654
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 402; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALUMINIUM 26
ASTROPHYSICS
BETA DECAY
CARBON
COSMIC DUST
HYDROGEN
INTERMEDIATE MASS NUCLEI
MAGNESIUM
MAGNESIUM 26
MASS TRANSFER
NEON
NUCLEAR REACTION KINETICS
NUCLEAR REACTIONS
NUCLEOSYNTHESIS
STAR ACCRETION
STAR EVOLUTION
THERMONUCLEAR REACTIONS
WHITE DWARF STARS