Astronomy and Astrophysics – Astrophysics
Scientific paper
Sep 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...433..216s&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 433, no. 1, p. 216-228
Astronomy and Astrophysics
Astrophysics
22
Cataclysmic Variables, Dwarf Novae, Nuclear Fusion, Stellar Interiors, Stellar Mass Accretion, Stellar Mass Ejection, White Dwarf Stars, Abundance, Hydrodynamics
Scientific paper
In an attempt to understand the manner in which nova outbursts are initiated on the surface of a white dwarf, we investigate the effects fluctuations have on the evolution of a thermonuclear runaway. Fluctuations in temperature density, or the composition of material in the burning shell may arise due to the chaotic flow field generated by convection when it occurs, or by the accretion process itself. With the aid of two-dimensional reactive flow calculations, we consider cases where a strong fluctutation in temperature arises during the early, quiescent accretion phase or during the later, more dynamic, explosion phase. In all cases we find that an instantaneous, local temperature fluctuation causes the affected material to become Rayleigh-Taylor unstable. The rapid rise and subsequent expansion of matter immediately cools the hot blob, which prevents the lateral propagation of burning. This suggests that local temperature fluctuations do not play a significant role in directly initiating the runaway, especially during the early stages. However, they may provide an efficient mechanism of mixing core material into the envelope (thereby pre-enriching the fuel for subsequent episodes of explosive hydrogen burning) and of mixing substantial amounts of the radioactive nucleus N-13 into the surface layers, making novae potential gamma-ray sources. This suggests that it is the global not the local, evolution of the core-envelope interface to high temperatures which dominates the development of the runaway. We also present a possible new scenario for the initiation of nova outbursts based on our results.
Arnett David
Shankar Anurag
No associations
LandOfFree
Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1788683