Mixing in classical novae: a 2-D sensitivity study

Casanova, Jordi; José, J.; Garcı́a–Berro, E.; Calder, A. C.; Shore, Steven N.

doi:10.1051/0004-6361/201015895

Cited by 33 publications

(40 citation statements)

References 36 publications

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“…This HI occurs ubiquitously in nature (Hasegawa et al, 2004;Casanova et al, 2011;Smyth and Moum, 2012), for example, in cloud layers (Dalin et al, 2010), in which case it is referred to as the Kelvin-Helmholtz instability (Landau and Lifshitz, 1959).…”

Section: The Hydrodynamic Instability (Hi) Modelmentioning

confidence: 99%

Kinneyia: A Flow-Induced Anisotropic Fossil Pattern from Ancient Microbial Mats

et al. 2016

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Kinneyia is the commonly used term to describe a class of trace fossil that is strongly associated with microbial mats. The appearance of Kinneyia (or wrinkle structures) in the fossil record has recently led to a number of possible mechanisms being proposed to explain its formation. Here, we outline, and critically compare, three of these models, involving formation of the characteristic ripple structures (i) in mats over liquefied sediment, (ii) by oscillatory flow of microbial aggregates, and (iii) by a Kelvin-Helmholtz instability of the mat surface. Of these models, our study shows that the hydrodynamic instability compares most favorably with the corresponding structures in the fossil record. Implications for the conditions under which the fossils formed are then further discussed.

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Section: The Hydrodynamic Instability (Hi) Modelmentioning

confidence: 99%

Kinneyia: A Flow-Induced Anisotropic Fossil Pattern from Ancient Microbial Mats

et al. 2016

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“…Observations of nova ejecta abundances provide evidence for dredge-up that enriches the envelope with heavy elements up to 30%-40% relative to solar ( [32] and references therein). Recently [33], [34] made 2D and 3D detailed surveys that confirm those results. …”

Section: The Reactive Flow -Mixingmentioning

confidence: 59%

Novae - The study of the reactive flow

Glasner

Truran

2012

J. Phys.: Conf. Ser.

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Abstract. There is a wide consensus in the astrophysics community that the mechanism underlying the observed Classical Nova eruptions is a surface thermonuclear runaway. We start this short review with the main observational facts that lead to the theoretical model of a thermonuclear runaway that takes place in an accreted hydrogen rich envelope placed on top of a cool degenerate core of a white dwarf. According to the theory, the accreted envelope becomes unstable to convection days to weeks prior to the runaway. During the extreme stages of the runaway itself, when the burning is most efficient, the envelope is fully convective. Therefore, the elements processed under such extreme conditions are lifted to the outermost regions of the star. A significant fraction of the envelope is ejected during the outburst. The complicated combination of hydrodynamic instabilities and explosive hydrogen burning, close to the surface of the star, gives us a unique opportunity to study this complex reactive flow. The range of core masses, core temperatures and accretion rates introduce a whole range of burning temperatures and densities. Following the description of the -standard‖ cases, we then focus on rare, but still possible, portions of the relevant parameter space, in which -breakout‖ of the traditional CNO cycle can occur and lead to heavy element enrichment patterns caused only by breakout burning. We conclude our review with the main challenges that nova theorists face today, with special emphasis on problems related to the nucleosynthesis issues.

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“…Recent efforts to disentangle this controversy have been performed with the hydrodynamic code FLASH. The results, reported in Casanova et al (2010Casanova et al ( , 2011, show that the onset of Kelvin-Helmholtz instabilities in the plasma drives efficient mixing through the core-envelope interface. The mean metallicity achieved in the envelope, Z ∼ 0.20-0.30, is in agreement with the observed values, hence demonstrating the feasibility of this mechanism.…”

Section: Multidimensional Nova Models: the Next Frontiermentioning

confidence: 97%

Classical and Recurrent Nova Models

José¹,

Casanova²,

Garcı́a–Berro³

et al. 2011

Proc. IAU

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Abstract. Remarkable progress in the understanding of nova outbursts has been achieved through combined efforts in photometry, spectroscopy and numerical simulations. According to the thermonuclear runaway model, novae are powered by thermonuclear explosions in the hydrogen-rich envelopes transferred from a low-mass stellar companion onto a close white dwarf star. Extensive numerical simulations in 1-D have shown that the accreted envelopes attain peak temperatures ranging between 10 8 and 4 × 10 8 K, for about several hundred seconds, hence allowing extensive nuclear processing which eventually shows up in the form of nucleosynthetic fingerprints in the ejecta. Indeed, it has been claimed that novae can play a certain role in the enrichment of the interstellar medium through a number of intermediate-mass elements. This includes 17 O, 15 N, and 13 C, systematically overproduced with respect to solar abundances, plus a lower contribution in a number of other species (A < 40), such as 7 Li, 19 F, or 26 Al. At the turn of the XXI Century, classical novae have entered the era of multidimensional models, which provide a new insight into the physical mechanisms that drive mixing at the core-envelope interface.In this review, we will present hydrodynamic models of classical novae, from the onset of accretion up to the explosion and ejection stages, both for classical and recurrent novae, with special emphasis on their gross observational properties and their associated nucleosynthesis. The impact of nuclear uncertainties on the final yields will be discussed. Recent results from 2-D models of mixing during classical nova outbursts will also be presented.

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Mixing in classical novae: a 2-D sensitivity study

Cited by 33 publications

References 36 publications

Kinneyia: A Flow-Induced Anisotropic Fossil Pattern from Ancient Microbial Mats

Kinneyia: A Flow-Induced Anisotropic Fossil Pattern from Ancient Microbial Mats

Novae - The study of the reactive flow

Classical and Recurrent Nova Models

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